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IEEE Transactions on Industrial Electronics
Journal Prestige (SJR): 2.192
Citation Impact (citeScore): 9
Number of Followers: 85  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0278-0046
Published by IEEE Homepage  [228 journals]
  • IEEE Industrial Electronics Society Information

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      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • IEEE Industrial Electronics Society Information

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      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • IEEE Transactions on Industrial Electronics Information for Authors

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      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Diagnosis of Interturn Short-Circuits in SRMs by High-Frequency Switching
           of Phases Amid Low-Torque Unaligned Rotor Positions

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      Authors: Mahetab Alam;Saifullah Payami;
      Pages: 7537 - 7546
      Abstract: The inherent problems of torque ripple, noise, and vibrations associated with switched reluctance motors (SRMs) are escalated when the machine is subjected to interturn short-circuits (ITSCs). Also, leaving it unchecked can ultimately lead to a complete winding short-circuit due to the insulation failure owing to the heat produced by locally generated hotspots. To avoid such ruinous damage, the diagnosis of ITSCs is very critical. This article proposes a method of diagnosing ITSCs by injecting high-frequency signals in the phases in their low-torque regions around unaligned rotor positions. The proposed method utilizes the drive power converter to inject and diagnose the ITSCs and, thus, requires no additional hardware. It has a higher sensitivity even toward minor fault conditions, i.e., as low as ITSC of four turns ($ approx$ 4% ITSC over a phase). The devised fault indicator is immune to load or speed variation and, hence, better detection reliability. Also, the method can diagnose the fault under load and speed transients, proving it to be more robust. Experiments are performed on a test rig of customized 8/6 SRM emulating the ITSCs to verify the potency of the proposed scheme.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Modified SVM Method for Three-Phase Quasi-Z-Source Rectifier With Fully
           Soft Switching Operation and Low Conduction Losses

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      Authors: Tuopu Na;Qianfan Zhang;Guoqiang Xu;Yunhao Yan;Xiang Chen;
      Pages: 7547 - 7556
      Abstract: The conventional ZSVM3 (quasi-Z-source space vector modulation) has been used for quasi-Z-source rectifier because it achieves zero voltage switching (ZVS) and zero current switching (ZCS) operation with wide range of output power and without any auxiliary circuits. However, this method cannot realize ZVS or ZCS at fully switching period, especially at the sector boundary, leading to low efficiency. To address this problem, in this article, a modified modulation based on ZSVM3 is proposed. The sequence of active vectors and zero vectors has been modified. Therefore, the ZVS and ZCS operation occurs at any time in one switching cycle, and the conduction losses decrease. Besides, the distribution of Mode 3 duration time is optimized, which increases the range of soft switching conditions. The operating principle of the proposed modified space vector modulation (SVM) is explained in detail. Then, the parameters design is developed. An experimental prototype is constructed to verify the effectiveness of the proposed modulation. Experimental results show that the grid-side total harmonic distortion (THD) and conduction losses reduce, all switches and free-wheeling diodes realize ZVS and ZCS operation at full range without any auxiliary circuit, and the highest efficiency is up to 96.87%.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A New Exponential Reaching Law Approach to the Sliding Mode Control: A
           Multilevel Multifunction Converter Application

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      Authors: Hasan Komurcugil;Sertac Bayhan;Naki Guler;Haitham Abu-Rub;
      Pages: 7557 - 7568
      Abstract: This article presents a new exponential reaching law (ERL) approach for the sliding mode control. Contrary to the existing reaching law methods, the proposed ERL does not employ a sign function and yields a faster reaching time. An expression of reaching time in terms of reaching law gains is derived analytically. The article will show that the reaching time to the sliding surface is very small provided that the gains are selected properly. The stability of the proposed reaching law will be proven. The proposed reaching law with sliding mode control is employed to control a 5-kW three-phase multilevel multifunction converter. It is shown that the system can operate as a rectifier, as a shunt active power filter (SAPF) or as a combination of both rectifier and SAPF simultaneously. Experimental results corresponding to each operation mode are presented to confirm the efficacy of the proposed reaching law under fast-changing nonlinear load currents.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Generalized Fault-Tolerant Model Predictive Control of Five-Phase PMSM
           Drives Under Single/Two Open-Switch Faults

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      Authors: Wentao Huang;Xiaofeng Zhu;Hengliang Zhang;Wei Hua;
      Pages: 7569 - 7579
      Abstract: To address both single open-switch fault (OSF) and arbitrary two OSFs of a five-phase permanent magnet synchronous motor (PMSM) drive, a generalized fault-tolerant model predictive current control method is proposed in this article. First, the postfault currents under OSFs are analyzed in the stationary frame based on the Fourier method. Then, to maintain torque output capacity and alleviate torque ripple, the optimal reference currents in fault scenarios are deduced with the principle of rotating magnetic motive force undisturbed. Further, the obtained phase currents are transformed into the rotating frame and applied in the cost function for the voltage vector optimization. Thus, the torque under postfault operations is guaranteed and the torque ripples are suppressed. Finally, various experiments are conducted to validate the feasibility of the generalized fault-tolerant control method of five-phase PMSM drives.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Simple Predictive Current Control of Asymmetrical Six-Phase Induction
           Motor With Improved Performance

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      Authors: Mohamed Mamdouh;Mohammad Ali Abido;
      Pages: 7580 - 7590
      Abstract: Despite the intensive research work on the application of model predictive control for multiphase machines, there are many challenges still to be handled such as high circulating currents, variable switching frequency, and high computation burden. This article proposes a simple, yet efficient predictive current control (PCC) for a six-phase induction motor that reduces considerably circulating current, computation cost, and switching frequency. In the proposed method, a group of four candidate voltage vectors (VVs) is formed in each control sample. Unlike similar methods reported in the literature, these candidate vectors are generated based on a simple lookup table and the previous optimal VV. The lookup table is designed such that it allows only one commutation in each control sample. The performance of the proposed method is assessed experimentally using a 1-kW asymmetrical six-phase induction motor. Different performance indices are investigated to compare the proposed method against two different PCC methods in literature at different operating conditions. The experimental results confirm that about a 50% reduction in average switching frequency and 15% in current total harmonic distortion at different speed ranges are observed with the proposed method compared to the conventional one.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Predictor-Based Data-Driven Model-Free Adaptive Predictive Control of
           Power Converters Using Machine Learning

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      Authors: Xing Liu;Lin Qiu;Youtong Fang;Jose Rodríguez;
      Pages: 7591 - 7603
      Abstract: In this article, a novel robust data-driven model-free predictive control framework based on the I/O data of the controlled plants, which is performed by incorporating the neural predictor-based model-free adaptive control and finite control-set model predictive control, is first proposed. The salient feature of the suggested framework is that the uncertainties, such as unmodeled dynamics and external disturbances, can be explicitly addressed in controlled systems. From a practical standpoint, however, the potential of this proposal is limited by a significantly increased online computational complexity, which makes it difficult to implement. To circumvent this limitation, a supervised imitation learning technique using data labeled is developed to imitate the known suggested controller, which the majority of the online computational burden can be transformed into offline computing by utilizing a trained artificial neural network subject to robustness characteristics. In particular, this development motivates a much simpler robust predictive control solution, which is convenient to implement in applications. Thus, by this proposal, the online implementation of much more complex predictive control strategies is made possible, and it explores a new possibility for future development of the complex control methodology. Finally, extensive simulative and experimental investigations for modular multilevel converter validate the interest and viability of the proposed design methodology.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Magnetic Integration for Multiple Resonant Converters

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      Authors: Yue Liu;Hongfei Wu;Zixian Ge;Guosheng Ji;
      Pages: 7604 - 7614
      Abstract: A universal integration method for the magnetic components (MCs) of multiple resonant converters is proposed in this article. Two rules for integration of multiple independent MCs are summarized, one of which is to keep functional independent of MCs after integration, while the other is to achieve lower loss and volume through integration. Following the proposed rules and by dividing an MC into winding-part and nonwinding-part, integration is achieved by sharing the nonwinding-part of the MCs. An input-series output-parallel (ISOP) resonant converter is taken as an example to show how integration is accomplished step by step. It is shown that, both volume and loss of the magnetic cores are reduced after integration of all the high frequency transformers and inductors. Detailed theoretical analysis, finite element analysis simulations and comparisons have been presented. A 600 V–800 V input, 28 V/2000 W-output ISOP resonant converter was built. Experimental results have been provided to verify the effectiveness and feasibility of the proposed integration methods.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Continuous-Control-Set Model Predictive Current Control of Asymmetrical
           Six- Phase Drives Considering System Nonidealities

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      Authors: Chee Shen Lim;Sze Sing Lee;Emil Levi;
      Pages: 7615 - 7626
      Abstract: Finite-control-set model predictive control (FCS-MPC) of multiphase (n-phase, n is assumed to be an odd number for simplicity) drives is challenging because of the large number of actual/virtual voltage vectors and the need for current control in (n–1)/2 subspaces (or planes; multiplane current control). Any suboptimal design (poor or no current control in some of the (n–1)/2 planes) may result in high individual plane current ripples, due to the low reactance. This work therefore investigates continuous-control-set (CCS) MPC for constant switching frequency multiphase motor drives as another alternative. The high-bandwidth CCS-MPC is designed to accurately account for system nonidealities, namely digital control and pulsewidth modulation delays, inverter dead time, and measurement noise. It will be shown that the CCS-MPC has the advantages of full voltage vector space access, regular switching characteristic, and improved cycle-by-cycle tracking control, while maintaining some of the known advantages of the FCS-MPC, e.g., intuitive cost function design, model-based control, and fast dynamics. The proposed control scheme is benchmarked experimentally against the classical, proportional-integral-based, field-oriented control in conjunction with an asymmetrical six-phase induction motor drive.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Speed Sensorless Control Method of Synchronous Reluctance Motor Based on
           Resonant Kalman Filter

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      Authors: Fengtao Gao;Zhonggang Yin;Cong Bai;Dongsheng Yuan;Jing Liu;
      Pages: 7627 - 7641
      Abstract: When estimating the active back electromotive force (AEMF) of synchronous reluctance motor (SynRM) at medium and high speed, the traditional Kalman filter (KF) will produce large phase delay due to the low-pass filter characteristics. A novel speed sensorless control scheme of SynRM based on resonant Kalman filter (RKF) is proposed in this article. First, the AEMF observer based on KF is designed and the bandwidth performance is analyzed. To solve the phase delay problem caused by KF, a generalized integral resonance perturbation estimator (GIRPE) is introduced to the framework of KF and the proposed RKF is formed. The estimation error of AEMF is compensated through GIRPE in the current error feedback loop of KF observer. In this way, the high-precision position estimation at high speed range is obtained. Finally, an improved dynamic position compensator is proposed to enhance the position estimation performance under dynamic case. The effectiveness of proposed scheme is validated at a 1.5-kW SynRM drive, and the computational burden of the proposed method is assessed quantitatively.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Generalized Data-Driven Model-Free Predictive Control for Electrical Drive
           Systems

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      Authors: Yao Wei;Hector Young;Fengxiang Wang;José Rodríguez;
      Pages: 7642 - 7652
      Abstract: The performance of model predictive control has a strong correlation to the precision of the physical parameters of the plant, and these parameters are hard to determine since they are continuously changing during the operation process. To fully eliminate the influence of the physical parameters and enhance robustness, a model-free predictive control is proposed in this article to suit the electrical drive systems. The plant model is designed as several discrete-time transfer functions used to decouple the input and output signals and to describe their relationships, and the coefficients of these functions are online designed based on the recursive least square algorithm. An observer is designed to obtain accurately sampled current components considering the delays. The proposed method is applied to a permanent magnet synchronous motor speed control system as the stator current controller, and the simulation and experimental results show the advantages of the improved dynamics, stator current quality, and robustness compared with the conventional model-free predictive current control strategy.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Robust Open-Circuit Fault Diagnosis for PMSM Drives Using Wavelet
           Convolutional Neural Network With Small Samples of Normalized Current
           Vector Trajectory Graph

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      Authors: Jun Hang;Xiaoman Shu;Shichuan Ding;Yourui Huang;
      Pages: 7653 - 7663
      Abstract: Open-circuit fault is one of the most common faults in permanent-magnet synchronous machine (PMSM) drives. The open-circuit fault can cause the obvious change of stator currents of the PMSM. Hence, the previous artificial-intelligence-based-fault diagnosis method mainly relies on the samples extracted from stator currents. However, the large sets of the samples are required due to the variation of the PMSM operating point, increasing the complexity of fault diagnosis. What is more, stator currents are easily affected by the noise, decreasing the accuracy of fault diagnosis. To solve the issues, this article proposes a robust open-circuit fault diagnosis method using the wavelet convolutional neural network with small samples of the normalized current vector trajectory graph. The proposed method uses current normalization to establish small sample sets and combines the convolutional neural network with discrete wavelet transform to enhance the robustness to noise. The proposed fault diagnosis method is validated by simulation and experiment. Both the results show that the proposed method can effectively diagnose 22 kinds of open-circuit fault types (including healthy mode), being with great antinoise ability and robustness to different working conditions.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Analysis and Elimination of Speed Measurement Ripple in Sinusoidal Coded
           Gearwheel Encoder for Spindle Motor Drive

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      Authors: Yunkyung Hwang;Jaehong Kim;
      Pages: 7664 - 7672
      Abstract: The gearwheel encoder with a magnetoresistive (MR) sensor is robust, simple, and widely used in high-speed industrial motor drives. Moreover, a high-precision rotor position detection is possible with the gearwheel encoder due to its large number of output pulses per revolution. The MR sensor outputs two sinusoidal signals that are 90 degrees apart, the period of which matches with one tooth of the gearwheel. However, these output signals are not perfectly sinusoidal because the MR sensor is manually mounted, and the magnitudes of these signals depend on the distance between the MR material and gearwheel. This slight imperfection in the output signals provokes large speed ripples in the speed measurement. This study analyzed the speed measurement ripples, and an effective ripple-elimination method was devised based on the results of the analysis. Ripple components caused by each signal error were calculated from the error signal models, and exact ripple frequencies were extracted. From the calculation results, a frequency adaptive series notch filter algorithm was designed. The simulation and experimental results demonstrated the effectiveness of the analysis and proposed approach. It is obviously shown through the experimental results that the speed measurement ripple is almost eliminated with the proposed method, and, thus, the analysis is valid.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Feedback Linearization and Robust Control for Whirl Mode With Operating
           Point Deviation in Active Magnetic Bearings-Rotor System

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      Authors: Ximing Liu;Xin Ma;Shiqiang Zheng;Jinxiang Zhou;Yulin Chen;
      Pages: 7673 - 7682
      Abstract: The whirl mode, seriously affecting the stability of active magnetic bearings (AMBs), is a hot issue in the AMBs-rotor system. This article stresses a whirl mode problem accompanied by the operating point deviation when the magnetically suspended control moment gyro outputs torque. A feedback linearization controller is proposed to decouple the whirl mode effects from the system state-space representation. A robust controller for uncertain systems is also used to solve the operating point deviation problem. First, the AMBs-rotor system's state-space representation containing the whirl mode terms is described. Next, a system uncertainty caused by the operating point deviation is discussed. Then, a feedback linearization controller combined with a robust controller for uncertain systems is designed. Finally, simulations and experiments for validity verification are presented, and comparative experiments with a PID controller and a robust controller are shown and compared in this article.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Torque-Ripple Reduction of Permanent Magnet Synchronous Machine Drives
           Based on Novel Speed Harmonic Control at Low-Speed Operation

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      Authors: Jianzhen Qu;Pinjia Zhang;Juri Jatskevich;Chengning Zhang;
      Pages: 7683 - 7694
      Abstract: Torque-ripple reduction methods based on harmonic current injection for permanent magnet synchronous machine (PMSM) drives have been widely discussed, while the performance of torque-ripple-model-based methods is limited due to model accuracy as well as the rotor position errors, and the speed harmonic control-based methods still cannot get rid of the impact of the phase information of speed harmonics, which results in remaining torque ripples and the difficulty in designing speed harmonic controller. In this article, the unique relationships between the quadrature magnitudes of speed harmonics and harmonic currents are derived considering the minimal conduction copper loss by the harmonic currents. Based on that, a novel torque-ripple reduction method based on the speed harmonic control is proposed, wherein a novel speed harmonic controller is presented to regulate the quadrature magnitudes of speed harmonics so that the phase of speed harmonics is avoided in the speed harmonic controller. Also, the proposed speed harmonic controller aims to generate harmonic current references. The proposed methodology is evaluated by experiments and is verified to reduce torque ripples of PMSM drives effectively.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Robust DPCC for IPMSM Based on a Full Parameter Identification Method

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      Authors: Yizhe Wang;Wu Liao;Sheng Huang;Ji Zhang;Meizhou Yang;Chengxu Li;Shoudao Huang;
      Pages: 7695 - 7705
      Abstract: This article proposes a robust deadbeat predictive current control (DPCC) method for the interior permanent magnet synchronous motor (IPMSM) based on a full parameter identification method. The DPCC method is innovatively combined with the high frequency currents injection method, which can observe inductances, flux linkage, and resistance values of the IPMSM online. After the parameter identification results are obtained, the initial crude parameters are replaced by the identification values in the DPCC method to enhance the robustness of the IPMSM control system. Moreover, a novel online accuracy verification method for parameter identification results is proposed to judge the error estimation level. The proposed method extracts the high bandwidth and the high parameter sensitivity characteristic of the DPCC method. The online identification and verification of IPMSM parameters are proceeded subsequently while achieving robust control of the IPMSM with the DPCC method. Finally, the proposed method is experimentally demonstrated with a 1.5 kW motor. The experimental results show that the IPMSM with the proposed method can still work well even in the situation of severe initial parameters mismatch.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Reduction of Cross-Coupling for Bearingless Doubly Salient Electromagnetic
           Motor Using Nonsynchronous Rotating Coordinate Transformation

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      Authors: Li Yu;Wei Chen;Qiuyu Xu;Zhuoran Zhang;Yuke Shi;
      Pages: 7706 - 7715
      Abstract: The cross-coupling between the X- and Y-axis suspension forces caused by the salient pole structure leads to unstable suspension control for bearingless doubly salient electromagnetic (BDSEM) motors. In this article, the cross-coupling characteristics of the 12/8-pole BDSEM motor are analyzed. The inherent orthogonality of the motor structure, as well as of the biased magnetic field, is illustrated. A new control method based on nonsynchronous rotating coordinate transformation is proposed. The suspension force characteristics in the proposed nonsynchronous rotating frame both under no-load and load conditions are studied by the mathematical model and finite element method. A 12/8-pole BDSEM motor and a suspension force controller are developed. The analytical and experimental results show that the suspension force cross-coupling of the BDSEM motor is reduced significantly.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Sensorless Control of Interior Permanent Magnet Synchronous Motor Drives
           Considering Resistance and Permanent Magnet Flux Linkage Variation

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      Authors: Abebe Teklu Woldegiorgis;Xinglai Ge;Yun Zuo;Huimin Wang;Mannan Hassan;
      Pages: 7716 - 7730
      Abstract: Extended sliding mode disturbance observer-based current observer for interior permanent magnet synchronous motors (IPMSM) is an efficient method, where the estimated dq-axis disturbances are linearly dependent on the position estimation error. Thus, this article proposed a robust speed-position identification strategy using the estimated disturbances. First, an analysis of the estimated disturbances concerning parameter variation, position estimation error, and the effect on the sensorless control performance is given. Then, a combined method that uses the dq-axis disturbances is proposed for speed-position identification. The proposed method is robust against stator resistance variation without estimating the stator resistance. However, the flux linkage variation effect sustains per the external load. Therefore, the permanent flux linkage variation electromotive force (EMF) compensator is included. The compensator is activated in the medium to the high-speed range while deactivated in the low-speed area. Thus, the advantage of the combined method for the low-speed area against resistance variation is kept. Various hardware-in-the-loop experimental studies and comparative analysis show that the proposed method with a permanent flux linkage variation back EMF compensator achieved an excellent sensorless control performance for IPMSM.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Design and Analysis of a Variable-Speed Constant-Amplitude Wind Generator
           for Stand-Alone DC Power Applications

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      Authors: Hao Chen;Ayman M. EL-Refaie;Yuefei Zuo;Shun Cai;Junfei Tang;Yujing Liu;Christopher H. T. Lee;
      Pages: 7731 - 7742
      Abstract: This article presents the design and analysis of a permanent magnet (PM) wind generator, which consists of two sets of windings, and two rotors. The proposed PM wind generator is designed for variable-speed constant-amplitude voltage operation in dc power applications, in order to maximize the utilization of wind energy and make the electricity more accessible to stand-alone situations, e.g., remote areas and offshore islands. The operating principle of the variable-speed constant-amplitude voltage operation of the proposed PM wind generator is demonstrated in detail. A comparative study is carried out among the proposed generator, a conventional surface-mounted PM synchronous generator, and an existing counterpart generator used for the same application. The results show that compared to the conventional PM synchronous generator and the existing counterpart, the proposed PM wind generator exhibits the advantages of high induced voltage, high torque/power density, high efficiency, etc. Finally, the proposed PM wind generator is prototyped and manufactured. The validity of the variable-speed constant-amplitude operation of the proposed generator under both steady-state and dynamic conditions, is verified by experimental results.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • High-Performance Induction Motor Speed Control Using a Robust Hybrid
           Controller With a Supertwisting Sliding Mode Load Disturbance Observer

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      Authors: Abdülhamit Nurettin;Nihat İnanç;
      Pages: 7743 - 7752
      Abstract: To enhance the speed control performance of a three-phase induction motor controlled by the vector control strategy, a new design of a hybrid controller (HC) is proposed based on the supertwisting algorithm (STA) and fuzzy approach. STA is chosen for its ability to decrease the ingrained chattering phenomenon in the classical sliding mode control with maintaining tracking precision and robustness. Nevertheless, the control gains included in the control law have an evident impact on suppressing the chattering phenomenon and increasing the system's dynamic response speed. Therefore, first, a robust HC based on the fuzzy logic control approach that operates as a fuzzy supervisor to online self-tune the value of the gains according to the system states is suggested to achieve high dynamic performance and limit the chattering effect. Second, to enhance the disturbance refusal capability, a supertwisting sliding mode load disturbance observer is developed to estimate the load torque disturbances. Then, the estimated disturbance is introduced into the equivalent control law. Subsequently, the system stability is verified by the Lyapunov theorem. Finally, the superiority of the proposed scheme is validated through comparison with the advanced and traditional controllers in simulation and experimental studies.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Pole-Transition Control of Variable-Pole Machines Using Harmonic-Plane
           Decomposition

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      Authors: Yixuan Wu;Gustaf Falk Olson;Luca Peretti;
      Pages: 7753 - 7760
      Abstract: Variable phase-pole machines have the potential to extend the operational range to higher speeds through magnetic pole changes. The state-of-the-art vector-space decomposition (VSD) cannot model the transient behavior of the pole change for any possible phase-pole configuration as it creates a discontinuity. The proposed harmonic-plane decomposition (HPD) theory solves this issue by generalizing the VSD to the fullest extent by using its discrete Fourier transformation interpretation. The theory for indirect rotor field-oriented control is developed using the HPD. A controlled, loaded pole change on a wound independently-controlled stator-coils machine using two transition strategies shows the HPD-based controller's ability to maintain torque in the transition. Additionally, the proposed controller accomplishes real harmonic injection and balanced steady-state operation.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Performance Comparison Between Permanent Magnet Synchronous Motor and
           Vernier Motor for In-Wheel Direct Drive

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      Authors: Yanlei Yu;Yulong Pei;Feng Chai;Martin Doppelbauer;
      Pages: 7761 - 7772
      Abstract: Nowadays, in-wheel drive mode is considered as one of the most promising modes for electric vehicles (EVs). The motor type plays a significant role in the vehicle performances. This article focuses on the performance between permanent magnet synchronous motor (PMSM) and permanent magnet Vernier motor (PMVM) for in-wheel direct drive. First, the required performances are determined by the vehicle requirements. The prototypes of PMVM and PMSM are manufactured after the comparison. Then, the expressions of air-gap magnetic field harmonic, electromagnetic torque, and power factor are theoretically derived, where the parameter torque ratio is introduced to evaluate the torque ratio between PMVM and PMSM. Based on experiment, the back-electromotive force harmonics, cogging torque, maximum torque per ampere capability, flux-weakening capability, torque, efficiency, and power factor are compared and analyzed. Subsequently, the discussions are carried out, where the strength and weakness of two-type motors for in-wheel drive are concluded and the future prospects are suggested. Finally, the conclusions of two-type in-wheel motors are then extracted. This article aims at providing a reference for the exploration of alternating in-wheel motor types, which can promote the development of high-performance in-wheel drive system for EVs.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Predictive Position Control With System Constraints for PMSM Drives Based
           on Geometric Optimization

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      Authors: Chun He;Jianhui Hu;Yong Li;
      Pages: 7773 - 7782
      Abstract: The system constraints (current, speed, and voltage limitations) are essential for the safety control of predictive position control (PPC) method. However, online solution of model predictive control with complex system constraints is still a challenge. In this article, a novel discrete-time model predictive position control (DMPPC) strategy for surface permanent magnet synchronous motor drive is proposed, the current, speed, and position are regulated simultaneously. The optimization model of the position control system considering system constraints is formulated, the current, speed, and voltage constraints are analyzed and transformed into the incremental voltage constraints. To reduce the calculation burden, a simplified method based on the geometric boundaries and cost function is proposed to solve the optimization problem, complex iterative calculations are avoided, the system constraints are well limited and less calculation time can be achieved. Finally, the proposed DMPPC method is experimentally verified and compared with a traditional iterative method and a cascade predictive position control (CPPC) method.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Phase-Shift-Modulated Resonant Two-Switch Boosting Switched-Capacitor
           Converter and Its Modulation Map

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      Authors: Shouxiang Li;Shengnan Liang;Zhenning Li;Shuhua Zheng;
      Pages: 7783 - 7795
      Abstract: In this article, a phase-shift-modulated resonant two-switch boosting switched-capacitor converter (RTBSC) and its modulation map are proposed. Compared with the traditional RTBSC, all diodes are replaced by active switches and then phase-shift modulation is applied. The advantages of the modified topology are obtained as follows. First, the voltage gain can be regulated efficiently either below or above the nominal value within wide range (about ±20%) even at light-load condition, making it suitable for applications with voltage fluctuations, such as the battery charging/discharging system, photovoltaic system and battery/PV voltage equalizer. Second, the conduction loss is reduced by replacing all diodes in RTBSC with low turn-on resistance transistors and adopting phase-shift modulation, especially for high-order and high-gain configuration. Third, all switches achieve the zero-voltage-switching (ZVS) turn-on, reducing the switching loss significantly. Fourth, the soft-charging property smooths the current profile. Aside from the topology modification, a comprehensive analysis of operation principle, voltage gain, component stress and ZVS region is given. On the basis, a modulation map with the optimal operation region is proposed. It provides a guideline to operate and design such converters in the target gain range, low component stress and ZVS region, making up for the lack of modulation map and design guideline. A 120W prototype with low-voltage side 43–60 V and high-voltage side 150 V was designed in the optimal operation region to verify the above analyses.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Balanced Dual-Side LCC Compensation in IPT Systems Implementing Unity
           Power Factor for Wide Load Range and Misalignment Tolerance

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      Authors: Shiying Luo;Zirui Yao;Zhuhaobo Zhang;Xin Zhang;Hao Ma;
      Pages: 7796 - 7809
      Abstract: Misalignment tolerance and wide load range capability are necessary for a practical inductive power transfer system. In pursuit of high performance, input unity power factor and high efficiency are expected. In this article, a balanced design method of dual-side LCC compensation is proposed to achieve input unity power factor over wide misalignment and load ranges. With the proposed method, dual-side LCC compensation is in a balanced state where zero phase angle frequencies coincide with designed voltage gain frequencies under coupling and load variations. Unity power factor can be implemented while maintaining voltage gain with frequency control. Possible output power versus frequency characteristics of this balanced dual-side LCC compensation are categorized and fully analyzed. One of them, with strong power regulation capability and high misalignment adaptability, is selected as the design target. Coil currents are optimized using a surplus degree of design freedom while selecting parameters. Unity power factor and coil current optimization ensure low losses in devices and coils, which benefits system efficiency. Thus, a wide load range, high misalignment tolerance, nearly zero reactive power, and high efficiency can be simultaneously implemented. The proposed method is verified on a 2.1 kW prototype. The coil size of both primary and secondary sides is 600 mm × 600 mm, and the air gap is 150 mm. Load power varies from 10% to 100% within the coupling range from 0.15 to 0.35. Nearly unity power factor is realized under various working conditions. The maximum dc–dc efficiency reaches 96.4%.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Perturbation Observation Method-Based Optimization Seeking Control of
           Soft-Switching and No Backflow Power for LCL Resonant-Type Dual Active
           Bridge DC–DC Converters

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      Authors: Mingxue Li;Xiaoqiang Li;Dongsheng Yu;Yang Leng;Chong Zhang;
      Pages: 7810 - 7820
      Abstract: LCL-type resonant dual active bridge (LCL-DAB) dc–dc converters feature high gain, high power density, and low reactive current. To further improve the efficiency, based on the dual-phase shift (DPS) modulation method, the operating characteristics are first derived and the design regions of soft-switching and no backflow power are established, and then a perturbation observation method-based optimization seeking control of soft-switching and no backflow power is proposed in this article. In the starting process, the system first tracks the reference voltage according to the relationship between the inner and outer phase shift ratio obtained by the first harmonic approximation. Then, the outer phase shift ratio is perturbed based on the characteristics of soft-switching and backflow power, approaching the target phase shift ratio stepwise, while the inner phase shift ratio is calibrated to hold the output voltage. Both H bridges can operate in soft-switching mode, and on this basis, the backflow power was eliminated to the maximum extent. Finally, the simulation and experimental results verified the feasibility and effectiveness of the proposed method.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • VNA-Based Fixture Adapters for Wideband Accurate Impedance Extraction of
           Single-Phase EMI Filtering Chokes

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      Authors: Huamin Jie;Si-Ping Gao;Zhenyu Zhao;Fei Fan;Firman Sasongko;Amit Kumar Gupta;Kye Yak See;
      Pages: 7821 - 7831
      Abstract: Differential-mode and common-mode chokes (DMC and CMC) are key components of electromagnetic interference filters. Accurate impedance knowledge of these chokes allows optimal EMI filter design to meet the conducted emission requirements. An impedance analyzer or vector network analyzer with a fixture adapter is commonly adopted for impedance measurement of a passive component. Usually, the non-standard terminals of both DMC and CMC make them incompatible for direct mounting on commercially available fixture adapters. Relying on additional interconnects to the fixture adapters introduce inherent parasitic effects that limit measurement accuracy up to several megahertz. This article proposes a design method of customized fixture adapters which are specifically tailored for impedance measurement of single-phase DMC and CMC. Through a systematic parasitic de-embedding process, the choke impedance can be extracted with excellent accuracy up to 120 MHz.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Robust Single-Loop Control Strategy for Four-Level Flying-Capacitor
           Converter Based on Switched System Theory

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      Authors: Wenjie Ma;Bo Zhang;Dongyuan Qiu;
      Pages: 7832 - 7844
      Abstract: For the four-level flying-capacitor converter (FFCC), it is required to simultaneously control the output voltage and balance the flying-capacitor voltages. Existing control methods for the FFCC always employ multiple control loops, where for every controlled voltage variable an independent control loop is to be designed. However, such a control structure of multiple loops leads to a complex coupling effect among these loops. Due to the coupling, it is difficult to achieve a coordinated design of a large number of control parameters and demonstrate the control system stability. To simplify the control design and the implementation, this article proposes a single-loop control strategy by using the switched system theory. All the voltages are driven towards their desired values with a single control loop, instead of using several individual controllers. Thus, the issue of devoting efforts to dealing with the couplings among multiple control loops is bypassed. Moreover, the system's large-signal stability is ensured in a straightforward manner, thereby simplifying the stability analysis. In the design process, the system parameter uncertainties are also considered. Comparative experiments demonstrate the good transient performance and the strong robustness of the proposed control strategy.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Double Bus Provider Asymmetrical Half Bridge Converter With a Resonant
           DCX-Derived Auxiliary Circuit to Supply a LED-Based VLC Postregulator

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      Authors: Theyllor Hentschke de Oliveira;Abraham Lopez Antuña;Daniel Garcia Aller;Diego G. Lamar;Manuel Arias;
      Pages: 7845 - 7854
      Abstract: The wide and settled use of Light-Emitting Diodes (LEDs) in lighting has made Visible Light Communication (VLC) an interesting option. Given the way LEDs are driven in VLC, the Two-Input Buck converter fits perfectly as a post regulator for VLC-LED lamps. Its main drawback is that it needs two input voltages with specific requirements tied to the VLC feature. One needs to be regulated according to the LEDs knee voltage thermal drift, while the other needs to be constant. With the objectives of avoiding complex circuits with cross regulation and using two converters performing the bus provider, the present work proposes a converter with two outputs that meet those voltage requirements. This converter is the integration of an Asymmetrical Half Bridge converter and a resonant unregulated Half Bridge converter. This integration is achieved thanks to the primary side similarity of both converters and the integration of both transformers, achieving a solution with fewer components. In addition, one output can be fully regulated by a standard control variable while the other remains naturally constant and independent. This greatly simplifies the control stage, avoiding cross regulation while fully complying with the application requirements. This work presents the circuit concept and how it relates to the intended application. The principle of operation will be explained and used to define the operational region where the topology meets the application requirements. To validate the proposed topology, a 45-W prototype is built and tested, archiving the output voltage requirements and an overall efficiency near 94%.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • An Improved High Voltage Pulse Generator With Few Nanoseconds Based on the
           Synergy of DOS and LTD Topologies for Supra Electroporation

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      Authors: Xian Cheng;Shuo Chen;Yanpeng Lv;Hui Chen;Buccur M. Novac;
      Pages: 7855 - 7866
      Abstract: Supra electroporation, also known as nanoelectroporation, induced by nanosecond pulse could increase organelle membrane permeability with negligible effect on cell membrane, which has been used for tumor treatment through immunogenic cell death. In order to investigate the supra electroporation of organelle membrane, this article proposes a new topology to generate high voltage pulse with few nanoseconds. This circuit topology contains two main stages: first, the topology of diode opening switch (DOS) with LC resonance boosting is used to generate few nanoseconds pulse. Second, for improving the output/input voltage gain, four DOS modules are optimally connected (two modules in parallel and another two modules in series) using linear transformer driver (LTD) structure. Moreover, the turn-on time of mosfet switch and the inductance of LTD windings are optimized to further boost the voltage amplitude. Finally, experimental results validate the functionality of the proposed topology. The output/input voltage gain can reach 24. This generator can output the nanosecond pulses with full width half maximum of 5.1 ns, amplitude of 3.7 kV (input voltage is 0.15 kV), and repetition frequency up to MHz with unipolar and bipolar polarity in burst mode.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Achieving Rated Power and ZVS for Dual Active Bridge Converter Considering
           the Interaction of Nonidealities

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      Authors: Haoyuan Jin;Yunqing Pei;Laili Wang;Junduo Wen;Chengzi Yang;Xiaobo Dong;
      Pages: 7867 - 7878
      Abstract: The transmitted power and zero-voltage-switching (ZVS) are two major concerns for dual active bridge (DAB) converters. They are influenced by some nonidealities in real applications, including MOSFET's nonlinear output capacitance, dead time in the bridges, as well as the mismatch between the transformer turns ratio and the input-to-output voltage ratio. Despite this, little work has been undertaken to give a detailed design method considering the interaction of these nonidealities. This article aims at achieving the rated power and ZVS for the DAB converter used as a dc transformer under single-phase-shift control by inductance range calculation. The interaction of these nonidealities is considered to select the inductance range for the first time. A 3.5–7 kW experimental prototype is built to verify the effectiveness of the proposed method.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Three-Level Resonant DAB Converter Featuring Minimized Circulating
           Losses for EV Battery Charging

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      Authors: N. J. Merlin Mary;Shelas Sathyan;Hiralal Muralidhar Suryawanshi;
      Pages: 7879 - 7890
      Abstract: A three-level modified series–parallel bidirectional isolated dc–dc resonant converter (TL-MSPBRC) is proposed for electric vehicle (EV) battery charging. The converter's performance is enhanced for wide load conditions as the modified series–parallel resonant tank is formed by considering the parasitics in the transformer. The first-harmonic approximation (FHA) equivalent circuit model is employed to analyze the converter characteristics for the frequency modulation technique. This converter has high conversion efficiency in charging and discharging operations because of the soft-switching capability of the power switches in the primary and secondary bridges. In addition, low on-state resistance switches in the three-level primary bridge minimize the conduction losses. A 3.3-kW converter prototype with a battery voltage range of 230$-$300-V is developed to validate the design method and the simulation results. The proposed converter has minimized circulating losses, good short-circuit protection, and excellent efficiency of 97.7% at the rated power level.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Voltage/Current Doubler Converter for an Efficient Wireless Charging of
           Electric Vehicles With 400-V and 800-V Battery Voltages

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      Authors: Francesca Grazian;Thiago Batista Soeiro;Pavol Bauer;
      Pages: 7891 - 7903
      Abstract: The lithium-ion battery of an electric vehicle (EV) is typically rated at either 400 or 800 V. When considering public parking infrastructures, EV wireless chargers must efficiently deliver electric power to both battery options. This can be normally achieved by regulating the output voltage through a dc–dc converter at the cost of higher onboard circuit complexity and lower overall efficiency. This article proposes a wireless charging system that maintains a high power transfer efficiency when charging EVs with either 400- or 800-V nominal battery voltage at the same power level. The control scheme is implemented at the power source side, and only passive semiconductor devices are employed on board the EV. The presented system, called voltage/current doubler (V/I-D), comprises two sets of series-compensated coupled coils, each of them connected to a dedicated H-bridge converter. The equivalent circuit has been analyzed while explaining the parameters' selection. The analytical power transfer efficiency has been compared to the one resulting from the conventional one-to-one coil system at 7.2 kW. For the same power level, the dc-to-dc efficiency of 97.11% and 97.52% have been measured at 400-V and 800-V voltage output, respectively. Finally, the functionality of the V/I-D converter has been proved at both the even and uneven misalignments of the two sets of coupled coils.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Nonisolated High-Step-Down DC–DC Converters With Low Component
           Count and Voltage Stress

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      Authors: Solmaz Baharlou;Mohammad Rouhollah Yazdani;Majid Delshad;
      Pages: 7904 - 7912
      Abstract: This article proposes two new nonisolated high-step-down dc–dc converters. The voltage conversion ratio of converters and the voltage stress of their semiconductor components are improved compared with the conventional buck converter. By coupling the inductors of the first proposed converter, its volume and price is reduced. By employing a clamp circuit with low elements to the first proposed converter, the second proposed converter is introduced, in which its voltage conversion ratio and the voltage stress of components are improved significantly; thus, in high-input-voltage applications, high-quality components (switches with low on-resistance and diodes with low forward voltage) can be used. In these converters, the leakage inductances of the coupled inductor are clamping, and their energy is recovered. The proposed converters have fewer elements than those of related high-step-down counterparts leading to lower volume and losses due to lower elements, increasing efficiency. The switches of the proposed converters switch simultaneously, reducing the converters' control circuit complexity. This article discusses the theoretical analysis and operational principle of both the proposed converters. Besides, to verify their performance, experimental results of the converters with 155-to-24-V input and output voltage are presented.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A New Single-Phase Flying Inductor-Based Common Grounded Converter for
           Dual-Purpose Application

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      Authors: Oleksandr Husev;Naser Vosoughi Kurdkandi;Milad Ghavipanjeh Marangalu;Dmitri Vinnikov;Seyed Hossein Hosseini;
      Pages: 7913 - 7923
      Abstract: This article presents a new common grounded flying inductor-based converter as power electronics interface suitable for application in both dc or single-phase ac grids using the same terminals. This topology enables direct connection of the negative terminal of the input dc power supply to the negative polarity of the converter output. Therefore, the leakage current is eliminated completely. The voltage boosting feature in single-stage and operation in a wide range of input dc power supply is the other benefit of the proposed solution. Since electrolytic capacitors are not used in the structure, the life of the converter is increased. The operation modes of the converter are explained in detail. Also, the design considerations for passive elements are discussed. To verify the accuracy of the performance of the proposed topology, a laboratory prototype (3.6 kW/6 kW) was built. Also, the related experimental results are presented.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Nonlinear Damping Output-Feedback Voltage Control for DC/DC Converters via
           Model-Independent Voltage Derivative Observer

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      Authors: Seok-Kyoon Kim;Sun Lim;Kyo-Beum Lee;
      Pages: 7924 - 7933
      Abstract: This paper proposes an output-feedback solution for DC/DC converter applications that considers model-plant mismatches and load variations as constraints in industrial applications. The following two major contributions of this study are particularly advantageous: (a) nonlinear damping terms to inject the critical damping performance into the closed-loop system with the cooperation of the feedback gain structure depending on the damping coefficients, and (b) estimation of the output voltage derivative by the model-independent observer with only one simple closed-loop eigenvalue and current feedback removal. The experimental study highlights the practical merit of the proposed solution by demonstrating the critical damping performance that suppresses the peak current level using a 3-kW bidirectional DC/DC converter.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Maximum Voltage Gain Tracking Algorithm for High-Efficiency of Two-Stage
           Induction Heating Systems Using Resonant Impedance Estimation

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      Authors: Kyung-Wook Heo;Juil Jin;Jee-Hoon Jung;
      Pages: 7934 - 7943
      Abstract: A boost power factor correction (PFC) circuit has replaced the diode rectifier to improve its poor power factor performance, low efficiency, and output power limitation for conventional induction heating (IH) applications. Accordingly, many studies have been conducted, but they considered only the efficiency of the boost PFC rather than the entire IH system, or their control and design were complicated. In this article, an algorithm tracking the maximum voltage gain of the resonant network is proposed to improve the entire efficiency of the two-stage IH system based on an exact online resonant frequency estimation. It can make the resonant network operate at the maximum voltage gain point which can improve the efficiency of the series-resonant inverter (SRI) included in the IH system with low circulating current, the minimum switching frequency, and zero voltage switching capability. The proposed algorithm also induces the minimum output voltage of the boost PFC, which can reduce its switching losses and total harmonic distortion. The validity of the proposed algorithm is experimentally verified using a 2.4-kW prototype IH system, including the boost PFC and the IH-SRI controlled by a digital signal processor.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • New Control Method for Receiver-Side DC–DC Converter With Large
           Stability Margin and Fluctuation Suppression Toward DWPT System

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      Authors: Qianfan Zhang;Xi Zhang;Weihan Li;Tengfei Hu;Yadong Wang;Shuanggang Shen;
      Pages: 7944 - 7954
      Abstract: Dynamic wireless power transfer (DWPT) system is applied to electric vehicles, medical treatment, communication, and many other fields. Usually, a dc–dc converter is cascaded at the receiver side to suppress output fluctuation caused by mutual inductance change in the moving process. However, there occurs instability in some conditions in the system under conventional topology and control method. This work proposes a new control method based on a dual buck–boost converter to handle the abovementioned two problems at the same time. It can, in theory, reduce the peak–peak and average values of dc inductor current, meanwhile, increasing the converter efficiency. Also, it can improve the stability margin of the whole system. In this article, we use a simulator to replace the actual DWPT system. Through the simulator, the WPT system can produce the same fluctuating output voltage as that under dynamic conditions to support experiment. The stability of the system is explored by constructing the small-signal model of the system. Then, the effectiveness of the method is proved by simulation and experimental results.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Family of Single-Phase Single-Stage Boost Inverters

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      Authors: Sze Sing Lee;Ricxon Jie Sheng Lim;Reza Barzegarkhoo;Chee Shen Lim;Felipe Bovolini Grigoletto;Yam Prasad Siwakoti;
      Pages: 7955 - 7964
      Abstract: H-bridge inverter is a common topology used for single-phase applications. Due to its limited voltage gain, a two-stage power conversion with a front-end dc–dc converter is usually adopted to accommodate the low dc source voltage. Recently, single-stage boost inverters are gaining significant interest due to their higher power efficiency and compactness. In this article, we present a family of boost inverters with continuous dc source current. By the incorporation of merely a power switch and a boost inductor to the first leg of H-bridge, voltage boosting and three-level generation can be simultaneously achieved within a single-stage operation. All potential topologies using the same number of components are derived. An extension to generate five voltage levels with voltage gain enhancement is also proposed. The operation of the proposed boost inverters is thoroughly analyzed. The simulation andexperimental results are presented for verification.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • An Accurate Power Model and High Power Density Design Method of
           Free-Standing Magnetic Field Energy Harvesters With H-Shaped Core

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      Authors: Huanyu Yang;Yong Li;Zhaowei Liu;Haijun Luo;Yihua Yan;Zhengyou He;
      Pages: 7965 - 7975
      Abstract: To achieve more output power of the free-standing magnetic field energy harvester (FSMFEH) with a smaller core volume, designing the core and coil parameters of FSMFEH is critical. However, the lack of an FSMFEH power model leads to the absence of a detailed design method. To address this issue, building an accurate FSMFEH output power model is required. In this article, by quantifying coil mutual inductance and internal resistance as core and coil parameters, an accurate power model of FSMFEH with all parameters is established based on the H-shaped core. As a result, based on the proposed model, the optimal values of the core column size, the core lamination size, the coil turns, and the wire diameter are designed. Experiment results show that the proposed model can maintain high accuracy, and the power density deviation is within 5% compared with the theoretical value. Besides, the optimized parameters designed according to the model analysis are effective for improving the power density. When the current of the busbar is 100 A, the maximum power density can reach 4.182 mW/cm3, and the corresponding maximum output power is 13.25 mW with the optimized parameters.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Interleaved Boost-Integrated LC Series Resonant Converter With
           Frequency-Free Designed Transformer for Wide Voltage Range Applications

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      Authors: Ben Dai;Mei Su;Guangfu Ning;Hui Wang;Kaiqiang An;
      Pages: 7976 - 7987
      Abstract: In this article, we present a novel interleaved boost-integrated LC series resonant converter with two output rectification modes, which are voltage-doubler rectifier mode and voltage-quadrupler rectifier mode with constant output voltage for wide input voltage range applications. Due to the symmetrical configuration of the rectifier, the voltage stress of switches and diodes on the secondary side is only half of the output voltage. With the proposed pulse frequency modulation, the maximum magnetic flux density Bm of high-frequency transformer is only related to the resonant frequency rather than the switching frequency. Hence, the transformer can be frequency-free designed. The zero-voltage switching of the primary switches and zero-current switching of the secondary switches and diodes are achieved, respectively. Moreover, the design procedure for some key parameters is presented. Finally, a 470 W prototype with a switching-frequency range from 50 to 140 kHz is built to verify the operation principles of the proposed converter and modulation.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Bidirectional Efficient Circuit Breaker With Automatic and Controllable
           Shutoff Functions for DC Distribution Network

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      Authors: Xiaoguang Diao;Fei Liu;Yizhan Zhuang;Shangzhi Pan;Xiaoming Zha;
      Pages: 7988 - 7999
      Abstract: Compared with the solid-state circuit breakers based on insulated-gate bipolar transistor and MOSFET, circuit breakers based on thyristors have higher capacity and lower cost, which have been extensively studied. However, the existing circuit breakers based on thyristors cannot achieve fast and reliable shutoff of the fault current. Therefore, a novel efficient bidirectional circuit breaker is proposed in this article, which has the functions of automatic and controllable shutoff. In any current direction, only one thyristor is conductive, which eliminates unnecessary power losses. The automatic shutoff function can cut off the fault current independently without detection delay. The controllable shutoff function can isolate the fault reliably without being affected by the line inductance. The proposed topology integrates the advantages of high efficiency, fast reaction, and high reliability. Although the existing bidirectional circuit breakers based on thyristors may have one of these advantages, no circuit breaker integrates all of them. Finally, the proposed circuit breaker is verified through simulation and experiment at 1.2 kW.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • DC-Link Voltage Dynamics of Three-Level Four-Wire Grid-Connected
           Converters During Harmonics Injection Operations

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      Authors: Sandro Guenter;Jiajun Yang;Giampaolo Buticchi;Friedrich W. Fuchs;Marco Liserre;
      Pages: 8000 - 8008
      Abstract: As the amount of decentralized electric power generation is steadily growing, not only the direction of power flow, but also the overall behavior of the grid changes. This means that harmonic voltages in the supply grid become more problematic. To deal with this problem, inverters of decentralized renewable energy resources can help to mitigate these harmonic grid voltages by injecting harmonic currents. However, this so-called active filter functionality leads to additional stress of the dc-link capacitor due to inevitable oscillations of the dc-link current and voltage. Hence, this article for the first time presents an analytical derivation of these dc-link oscillations caused by a harmonic current injection into the grid. The analysis is presented for two-level and three-level inverters with split dc-link in a four-wire configuration. Simulation and experimental measurement results show the validity of the proposed analytical calculations. Furthermore, the impact of these dc-link harmonics on the capacitor lifetime is discussed. An exemplary scenario with a 10-KW photovoltaic inverter mitigating a 5th-harmonic grid voltage shows a possible lifetime reduction of the dc-link capacitor of up to 52% due to the oscillations in the dc-link voltage and current. Thus, this article aims to raise awareness of converter designers regarding this lifetime reduction, so that they take these oscillations into account during the design process and avoid unexpected early failure of the dc-link capacitor.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Virtual-Flux State Observer-Based Inductance Identification Method for
           Model Predictive Control of Grid-Tied Inverters With a Finite Phase Angle
           Set-Based PLL

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      Authors: Leilei Guo;Han Xiao;Hailiang Zhao;Zhiyan Zhang;Changzhou Yu;Xiaoliang Yang;Hong Zhu;
      Pages: 8009 - 8021
      Abstract: To reduce the calculation burden of the conventional finite phase angle set-based phase-locked loop (PLL) and enhance the parameter robustness of the model predictive control for grid-tied inverters, an improved finite phase angle set-based PLL and a new inductance identification method based on virtual-flux state observer (VFSO) are proposed in this article. First, three improved PLLs are proposed based on the principles of the conventional finite phase angle set-based PLL. Second, the proposed PLLs are further improved by redesigning the cost function, which can search the optimal phase angle within the region of [0, π] instead of [0, 2π], reducing the iteration times. Third, a new VFSO with only one observer parameter is proposed, based on which a new inductance identification method is presented. Fourth, by analyzing the characteristics of the proposed VFSO, it is found that a larger observer gain can improve the dynamic convergence speed of the proposed VFSO, while a smaller one can enhance its robustness against grid frequency deviation. So, an observer gain adaptive method is proposed, aiming to improve both the dynamic and steady-state control performance of the proposed inductance identification method. Finally, comparative experimental studies verify the effectiveness of the proposed strategies.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Rectifier-Reusing Bias-Flip Energy Harvesting Interface Circuit With
           Adaptively Reconfigurable SC Converter for Wind-Driven Triboelectric
           Nanogenerator

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      Authors: Sang-Han Lee;Yeon-Woo Jeong;Sang-Jae Park;Se-Un Shin;
      Pages: 8022 - 8031
      Abstract: The energy harvesting interface circuit is proposed for wind-driven triboelectric nanogenerator (WD-TENG). To extract power from the WD-TENG maximally and deliver power to the output (battery) efficiently, a rectifier-reusing bias-flip (RRBF) technique and a multiphase reconfigurable switched-capacitor converter (MRSCC) are developed. In the RRBF, the low-side switches of the rectifier are reused as switches for bias-flip without additional components. The MRSCC delivers power to the battery efficiently by reducing switching loss including overlap loss. Furthermore, the MRSCC maintains a rectified voltage (VRECT) as high as a breakdown voltage (VBR) of a switch by adaptive conversion control and multiphase operation to extract maximized power from the WD-TENG in a given process, even if the battery voltage is varied from 2.7 to 4.2 V. Owing to the proposed techniques, the maximum extracted power to the output is 238 μW and peak power delivering efficiency of the MRSCC is 79.3%. The chip was fabricated in 0.18 μm BCD process.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Multidimensional Ripple Correlation Technique for Optimal Operation of
           Triple-Active-Bridge Converters

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      Authors: Ahmed A. Ibrahim;Tommaso Caldognetto;Davide Biadene;Paolo Mattavelli;
      Pages: 8032 - 8041
      Abstract: This article presents a multidimensional ripple correlation search technique of optimal operating points of triple-active-bridge (TAB) converters. Such converters present multiple modulation parameters that should be exploited to achieve high operation efficiency. On the other hand, the several degrees of freedom available make the identification of optimal parameters a challenging task, not easily tackled analytically or in closed form. A model-free online search method based on the ripple correlation technique is then proposed in this article. The proposed method finds the optimum modulation parameters of TAB converters utilizing a three-dimensional ripple correlation control. The key property of the proposed solution is the adoption of orthogonal perturbation signals, where the orthogonality is simply obtained using different injection frequencies. The multidimensional correlation technique originally shown herein can be applied to other generic optimization problems. The proposed search is verified through a hardware-in-the-loop validation setup and an experimental prototype rated 5 $mathrm{k}mathrm{W}$.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Multivector Model Predictive Current Control for Paralleled Three-Level
           T-Type Inverters With Circulating Current Elimination

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      Authors: Tong Liu;Alian Chen;Yaopeng Huang;
      Pages: 8042 - 8052
      Abstract: Paralleled three-level T-type inverters face the unavoidable pitfall of the zero-sequence circulating current (ZSCC). Although the conventional model predictive control (MPC) could eliminate the ZSCC, the control error occurs inevitably since only one vector is adopted in each sampling period, which decreases the current control performance. Thus, simultaneous ZSCC elimination and accurate current tracking become imperative to the inverter using MPC. This article proposes a multivector MPC to eliminate the ZSCC and reduce the current distortion without the weighting factor. As the common-mode voltage (CMV) and neutral point (NP) voltage are the main factors that induce the ZSCC, the virtual vector with zero-average CMV is constructed to eliminate the ZSCC. Meanwhile, the small vector is introduced to improve the NP voltage control capability. In addition, to enhance the current accuracy and reduce the ZSCC ripple, three optimal vectors are adopted to synthesize desired voltage. Moreover, the multivector preselection algorithm is proposed to reduce the computational complexity of implementation process. Finally, the effectiveness of the proposed method is verified with comprehensive simulation and experimental results.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Distributed Edge-Based Event-Triggered Control for Voltage Restoration and
           Current Sharing in DC Microgrids Under DoS Attacks

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      Authors: Jinghang Lu;Haiyang Jiang;Xiaochao Hou;Peng Wang;
      Pages: 8053 - 8063
      Abstract: In the dc microgrid, the dc bus voltage recovery and proper current sharing may be a challenging task under the denial of service (DoS) attacks. To get around this issue, a distributed edge-based event-triggered control (ETC) strategy is proposed in this article. It is shown that the proposed technique could eliminate the dc bus voltage deviation and achieve proper current sharing under the DoS attacks by designing a new sampling and triggered mechanism. As a result, the system can effectively resist the DoS attacks, and the communication burden can be greatly relieved. Besides, the system's stability is proved by the Lyapunov theory, and it demonstrates that the edge-based event detector is able to guarantee the asymptotic stability of the dc microgrid under DoS attacks. Finally, the experimental case studies are presented to verify the feasibility of the proposed control method.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Decoupled Mitigation Control of Series Resonance and Harmonic Load Current
           for HAPFs With a Modified Two-Step Virtual Impedance Shaping

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      Authors: Yunfeng Li;Jinwei He;Yu Liu;Yongfeng Ren;Yun Wei Li;
      Pages: 8064 - 8074
      Abstract: Hybrid active power filter (HAPF) with large series capacitor can reduce the rating of power converter, but it is associated with the risk of low frequency LC resonance. The overlapping of series LC resonance frequencies and the dominated load harmonic current frequencies makes the conventional active damping approaches less effective. To overcome this challenge, a two-step harmonic virtual impedance control approach is developed to compensate the load harmonic current and reshape the closed-loop equivalent circuit of the HAPF for resonance damping. First, the shunt capacitor harmonic voltage is regulated according to a term that is associated with both the harmonic load current and the HAPF harmonic line current. Further investigation on the equivalent circuit transformations indicates that HAPF is equivalent to a controlled current source to compensate for load harmonic current and a virtual harmonic damping resistor between the series capacitor and grid impedance. Accordingly, the resonance damping and the nonlinear load low order harmonic current compensation can be well decoupled with minimal interference.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Modeling and Transient Stability Analysis for Type-3 Wind Turbines Using
           Singular Perturbation and Lyapunov Methods

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      Authors: Yumei Ma;Donghai Zhu;Ziqin Zhang;Xudong Zou;Jiabing Hu;Yong Kang;
      Pages: 8075 - 8086
      Abstract: Wind turbines (WTs) are prone to transient instability during weak grid faults, which is caused by their complex interactions. However, it is a challenge to analyze the transient stability, due to high-order and strong nonlinearity. Moreover, the existing works mainly focus on a phase-locked loop (PLL) system while ignoring current control, which cannot fully reflect the transient instability mechanism. To fill this gap, this article studies the transient stability of type-3 WT considering both PLL and current control. First, to simplify the full model of type-3 WT, a slow–fast subsystem is established using the singular perturbation. Then, the sixth-order full model is simplified as a second-order slow subsystem and its small disturbance (i.e., fast subsystem). Based on it, Lyapunov's direct and indirect methods are adopted to analyze the stability of slow and fast subsystems, respectively. Meanwhile, the influence of various factors (e.g., the fault degree, grid inductance, current references, current controller, and PLL controller) on transient stability of type-3 WT is revealed. In addition, the proposed analytical method combining singular perturbation and Lyapunov methods is a new approach to studying transient stability, which can also be applied to other renewable energy resources. Finally, the analysis is validated by experiments.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Highly-Efficient and Cost-Effective Ripple-Free Resonant NPC DC–DC
           Converter

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      Authors: Tsegaab Alemayehu Wagaye;Hyun-Sam Jung;Minsung Kim;
      Pages: 8087 - 8097
      Abstract: This article presents highly-efficient and inexpensive ripple-free resonant neutral-point-clamped (NPC) dc–dc converter that does not use extra inductors. By using the push–pull transformer itself, with the primary-side switching modulation fixed at 0.5, the proposed converter accomplishes theoretically zero input current ripple. Because of the resonant NPC cell, the circuit does not experience instantaneous reactive current flow regardless of wide input voltage variation. The resonant NPC structure much reduces the voltage stress at the turn-off instant; this aspect enables use of inexpensive low-voltage-rated active power components. Therefore, the proposed converter is inexpensive, highly efficient, and has high power density. A 1-kW experimental prototype was implemented and it was tested to validate the superior properties of the proposed converter.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Research on Power Decoupling and Parameter Mismatch of Three-Port Isolated
           Resonant DC–DC Converter Applied Switch-Controlled Capacitor

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      Authors: Xinsheng Zhang;Hongchen Liu;Patrick Wheeler;Fengjiang Wu;
      Pages: 8098 - 8107
      Abstract: In order to realize the controllable power decoupling and eliminate the influence of the parameter error of the resonant elements, a three-port dc–dc converter applied switch-controlled capacitor (SCC) is proposed. The operating principle and transmission power expression of the proposed three-port converter under triple-phase-shift control are analyzed. By adjusting the phase-shift angle of the SCC to adjust the resonant frequency of the resonant tanks, the topology-level power decoupling of the circuit at a constant frequency can be achieved. The addition of switch-controlled capacitors provides more freedom for power regulation between ports. Besides, according to the proposed converter, a design method for the parameters of the resonant tank is proposed to eliminate the adverse effects caused by the parameter error of the resonant elements. Then, an optimized triple-phase-shift modulation strategy is adopted to achieve the minimum rms value of the resonant converter. An experimental prototype was designed to verify the correctness of the proposed converter and modulation strategy.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Analysis of a Multifunctional Inverter Active-Filtering Function Influence
           on the Small-Signal Stability of Inverter-Based Islanded AC Microgrids

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      Authors: Sebastián de Jesús Manrique Machado;Sérgio Augusto Oliveira da Silva;José Roberto Boffino de Almeida Monteiro;Leonardo Poltronieri Sampaio;Azauri Albano de Oliveira;
      Pages: 8108 - 8117
      Abstract: This article deals with the small-signal analysis of islanded ac microgrids, considering the coexistence of voltage-controlled converters operating under droop control law and current-controlled converters (CCC) operating as multifunctional inverters. Thus, the CCCs can deliver power from a nondispatchable energy source and, depending on the operation mode, they can perform the active filtering function (AFF), which consists of injecting the harmonic currents associated with the local nonlinear loads (NLL) resulting in a microgrid power quality improvement. However, the transient characteristics following a local NLL step highly depend on the CCC operation mode. When AFF is disabled, the CCC output is almost not affected by the local NLL step. Instead, the harmonic extraction algorithm dynamics affect the CCC output when AFF is enabled. As a result, the overall system dynamic behavior is significantly affected, since microgrids are low-inertia and small power systems. A generic small-signal model is derived to study these effects, and its accuracy is then validated through simulated and experimental results. It was found through time-domain and frequency-domain sensitivity analyses that the AFF significantly affects the CCC phase-locked loop and the dynamic interactions between the microgrid network and the inverter's internal control loops.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Flexible Power Control for Extending Operating Range of PV–Battery
           Hybrid Cascaded H-Bridge Converters Under Unbalanced Power Conditions

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      Authors: Hao Xue;Jinwei He;
      Pages: 8118 - 8128
      Abstract: Due to the nonuniform solar irradiance, different temperature, and inconsistent module features, the output power among each photovoltaic (PV) module in a single-phase cascaded H-bridge (CHB) inverter is unequal. The H-bridge module with higher power generation faces the risk of overmodulation. To further extending the operating range of the CHB PV inverter under unity power factor condition, in this article, a battery module is connected with the system in series to form a PV–battery hybrid CHB converter. Meanwhile, the corresponding flexible power control strategy is proposed. The injected power of the battery module is controlled adaptively according to the maximum modulation index of all PV modules. With the proposed approach, all PV modules are free from overmodulation even with severe power imbalance, and thus, more energies are harvested. The effectiveness of the proposed control method is verified by experimental results.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Unified Active Damping Strategy Based on Generalized Virtual Impedance in
           LCL-Type Grid-Connected Inverter

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      Authors: Wei Chen;Yan Zhang;Yiming Tu;Yuanpeng Guan;Ke Shen;Jinjun Liu;
      Pages: 8129 - 8139
      Abstract: Extensive solutions have been proposed to damp LCL filter resonance. However, the time delay caused by computation and modulation process aggravates the complexity of current loop analysis. In this article, a generalized virtual impedance model for six kinds of commonly used active damping methods is proposed, and the physical meaning is established by introducing the metric of “damping factor.” To ensure system robustness in a wide range of grid conditions, a hybrid active damping strategy that combines inverter current feedback and capacitor voltage feedforward is proposed. Importantly, this method only requires inverter current and capacitor voltage sensors, which are the basic variables for over-current protection, power control, and synchronization. The superposition theorem is also utilized to analyze the damping capability provided by parasitic resistances, current feedback loop, and voltage feedforward loop. Finally, experimental results verify the feasibility and robustness of the proposed damping method.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Addressing Amplitude and Phase Coupling Problem in Grid Synchronization
           Systems

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      Authors: Saeed Golestan;Josep M. Guerrero;Abdullah M. Abusorrah;Muhyaddin J. H. Rawa;Juan C. Vasquez;Jose Rodriguez;
      Pages: 8140 - 8150
      Abstract: In many grid synchronization systems (GSSs), amplitude and phase estimation loops are dynamically coupled. It means that a change in the input voltage amplitude may result in spurious phase/frequency transients in the GSS output and vice versa. This article aims to explain the reason behind this coupling and present some guidelines to mitigate it. Several case studies are provided, and numerical and experimental results are presented to make all this more clear.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Robust Predictor-Based Control for Multirotor UAV With Various Time Delays

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      Authors: Seong-Min Lee;Minho Shin;Hungsun Son;
      Pages: 8151 - 8162
      Abstract: This article presents a robust predictor-based sliding-mode control (RPSMC) for multirotor unmanned aerial vehicles (UAVs) to ensure desired tracking control under time delays, which appear in practice by communications, complex computation, and actuator delays. Many UAV applications have difficulty in control and operation due to various types of time delays, resulting in repeated commands, severe control instability, and then mission failure. However, existing controllers have limitations in solving time delay problems. In this article, the RPSMC with the prediction of future disturbance and reference trajectory is developed for the multirotor UAV to minimize the effects of time delay, robustly deal with external disturbances, and further achieve desired tracking control. The performance of RPSMC for the multirotor UAV is verified under various time delays and disturbances in numerical simulations. The results show the robustness and fast control convergence compared with proportional-integral-differential and conventional predictor-based controllers. Experimental results with step response and tracking of circular trajectory demonstrate the feasibility and performance of the RPSMC for UAVs in the presence of various time delays and disturbances.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Robust and Accurate Monocular Pose Tracking for Large Pose Shift

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      Authors: Qiufu Wang;Jiexin Zhou;Zhang Li;Xiaoliang Sun;Qifeng Yu;
      Pages: 8163 - 8173
      Abstract: Tracking the pose of a specific rigid object from monocular sequences is a basic problem in computer vision. State-of-the-art methods assume motion continuity between two consecutive frames. However, drastic relative motion causes large interframe pose shifts, especially in applications such as robotic grasping, failed satellite maintenance, and space debris removal. Large pose shifts interrupt the interframe motion continuity leading to tracking failure. In this article, we propose a robust and accurate monocular pose tracking method for tracking objects with large pose shifts. Using an indexable sparse viewpoint model to represent the object 3D geometry, we propose establishing a transitional view, which is searched for in an efficient variable-step way, to recover motion continuity. Then, a region-based optimization algorithm is adopted to optimize the pose based on the transitional view. Finally, we use a single-rendering-based pose refinement process to achieve highly accurate pose results. The experiments on the region-based object tracking (RBOT) dataset, the modified RBOT dataset, the synthetic large pose shift sequences, and real sequences demonstrated that the proposed method achieved superior performance to the state-of-the-art methods in tracking objects with large pose shifts.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • An Efficient Online Loop Closure Detection System With Local Spatial
           Co-Occurrence Information

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      Authors: Lijun Zhang;Weisheng Yan;Huiping Li;
      Pages: 8174 - 8183
      Abstract: As a vital component in simultaneous localization and mapping techniques, appearance-based loop closure detection (LCD) plays important roles in bounding the long-term drift errors. In this article, an online LCD system based on the mutual co-occurrence information among visual features is proposed. First, a feature tracker module is designed to generate distinctive visual words, exploiting tracked words tool to improve efficiency. Then, an incrementally built vocabulary is organized by a hierarchical navigable small world graph, where the visual words are indexed. To merge a homologous word into the existing one, the vocabulary applies an improved high-dimensional online clustering method, which regards individual cluster as a normal distribution form. At the query phase, a list of candidate frames is located due to the co-occurrence constraint. Ultimately, the loop closure is specified by passing the temporal and similarity check, which avoids the memory consumption of historic image data. Validation tests based on public datasets and experimental sequences demonstrate the merit of low running time and memory cost while the high-precision performance is retained in the system.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • TICBot: Development of a Tensegrity-Based In-Pipe Crawling Robot

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      Authors: Yixiang Liu;Qing Bi;Xiaolin Dai;Rui Song;Jie Zhao;Yibin Li;
      Pages: 8184 - 8193
      Abstract: This article presents the development of a novel tensegrity-based robot, TICBot, which is capable of crawling in tubular environments. Based on the concept of tensegrity, a deformable robotic module consisted of discrete rigid struts and a continuous net of elastic springs is proposed. Then, the in-pipe crawling robot is designed by serially cascading three uniform modules. The mechanical structure of the robotic module is determined using force density method on the basis of kinematic and static analysis. Performance of the robot in aspects of shape changeability, mobility, load capacity, and adaptability are tested on the prototype. Experimental results show that the robot has the abilities to crawl in pipes with different inner diameters and shapes, and to pass through elbow pipes adaptively under the control of a simple actuation sequence. Compared with existing robots, this proposed approach enables more compact structures along with enhanced mobility and adaptability. This article validates the effectiveness of our proposal and provides a new approach for developing in-pipe crawling robots and other bioinspired robots.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A New Insect-Scale Piezoelectric Robot With Asymmetric Structure

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      Authors: Jie Hu;Si Chen;Le Wang;
      Pages: 8194 - 8202
      Abstract: To realize the switching of the multiple locomotion modes, a new insect-scale piezoelectric robot with asymmetric structure is proposed, fabricated, and tested. The robot prototype has a weight of 32.8 g and size of 55 ×50 ×20 mm. Driven by two pieces of piezoelectric ceramics, working at six vibration modes, the piezoelectric robot can realize two kinds of linear motion and four kinds of circular motion by contact friction. Performance assessments show that the robot has a maximum velocity of 155 mm/s and a minimum motion radius of 45 mm. In addition, the robot can move at a speed up to 97 mm/s (100 Vp-p) with an integrated drive device (45.7 g). The insect-scale piezoelectric robot has simple structure, but has multiple motion modes, large speed range, good output characteristics, and fast response time, which provides a new idea for the design and driving of microrobot.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Robust Pixel-Wise Prediction Network With Applications to Industrial
           Robotic Grasping

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      Authors: Xuebing Liu;Xiaofang Yuan;Qing Zhu;Yaonan Wang;Hui Zhang;Mingtao Feng;Zijie Wu;Yongpeng Tang;
      Pages: 8203 - 8214
      Abstract: Accurate object detection and 6D pose estimation are the key technologies in robotic grasping applications, where efficiency and robustness are the two most desirable goals. Especially, for textureless industrial parts, it is difficult for most existing methods to extract robust image features from cluttered scenarios with heavy occlusion. To address this challenge, we propose a novel pixel-wise prediction strategy using local features to infer global information based on the inherent local–global relations of rigid objects. This strategy is robust to missing or disturbed local information since each pixel has an independent prediction, and the dense prediction manner can mitigate the instability caused by outliers. Accordingly, we first generate dense pixel-wise predictions of the object category, center, and keypoint from image features extracted by an encoder–decoder network. Then, these predictions are used to vote on and identify the keypoint locations of the specific instance object, and finally, the poses are estimated from the keypoints by an uncertainty perspective-n-point (PnP) algorithm. Experiments on various scenarios are implemented to illustrate the advantages of our approach on severe industrial scenes, and a robotic grasping platform is constructed to evaluate its application performance.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Long-Endurance Flapping-Wing Robot Based on Mass Distribution and Energy
           Consumption Method

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      Authors: Xiaoyang Wu;Wei He;Qiang Wang;Tingting Meng;Xiuyu He;Qiang Fu;
      Pages: 8215 - 8224
      Abstract: Flapping-wing robots (FWRs) have great potential in comprehensively optimizing the flexibility, cruising speed, load capacity, and the robot mass. Recently, researchers have focused on small-wingspan FWRs but with a large limitation of the payload and endurance. In this article, we design an eagle-like FWR with a vision system and a flight control system, where the wingspan is as long as 1.78 m and the mass is 985 g (without the vision system). Even though the FWR carries a vision module weighing 165 g, it can cruise for more than 1 h where the flight speed frequently reaches 5.9 m/s. If the FWR removes the vision system and further adds a 132-g battery, the flight time can be increased to 95–110 min. By considering the vision module as a payload, according to the mass distribution method and successful FWR examples, we roughly determine the mass of the electronic system and the FWR structure. The FWR structure is designed to satisfy the mass limitation and, most importantly, guarantee the endurance as long as possible. This structure optimization, although is not unique, is of large novelty and different from the formulaic mass distribution method.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • SeqOT: A Spatial–Temporal Transformer Network for Place Recognition
           Using Sequential LiDAR Data

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      Authors: Junyi Ma;Xieyuanli Chen;Jingyi Xu;Guangming Xiong;
      Pages: 8225 - 8234
      Abstract: Place recognition is an important component for autonomous vehicles to achieve loop closing or global localization. In this article, we tackle the problem of place recognition based on sequential 3-D LiDAR scans obtained by an onboard LiDAR sensor. We propose a transformer-based network named SeqOT to exploit the temporal and spatial information provided by sequential range images generated from the LiDAR data. It uses multiscale transformers to generate a global descriptor for each sequence of LiDAR range images in an end-to-end fashion. During online operation, our SeqOT finds similar places by matching such descriptors between the current query sequence and those stored in the map. We evaluate our approach on four datasets collected with different types of LiDAR sensors in different environments. The experimental results show that our method outperforms the state-of-the-art LiDAR-based place recognition methods and generalizes well across different environments. Furthermore, our method operates online faster than the frame rate of the sensor.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Resonant-Type Thin Plate Piezoelectric Actuator Inspired by
           Koala's Locomotion

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      Authors: Yingzhi Wang;Jie Deng;He Li;Xinqi Tian;Weishan Chen;Yingxiang Liu;
      Pages: 8235 - 8243
      Abstract: Imitating the behavioral traits or structures of biological organisms can provide new ideas and operating principles for designing microactuators. Inspired by the locomotion of koalas, a lightweight self-locomotion piezoelectric actuator (SLPA) is developed. Based on the hybrid of the longitudinal and bending vibration modes, the proposed SLPA is able to obtain linear locomotion. The configuration of the SLPA is designed based on a thin metal plate with miniature size of 19.5 × 19.5 × 1.1 mm3. The operating principle is verified through the finite element analysis simulation. The experimental results show that the prototype achieves maximum speed of 61.68 mm/s and slope angle of 20° when the excitation frequency and voltage are 19.75 kHz and 50 Vp-p, which demonstrates the validity of the proposed SLPA climbing on slopes and the effectiveness of the proposed operating principle. Furthermore, the step displacement resolution of 2.2 μm is obtained by the proposed SLPA under the resonant working state. Finally, a simple optical focusing system is established to verify the feasibility of potential application of micropiezoelectric actuator.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Topology Optimization of the IPMSMs Considering Both the MTPA and FW
           Controls Under the Voltage and Current Limitations

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      Authors: Changwoo Lee;In Gwun Jang;
      Pages: 8244 - 8253
      Abstract: This article proposes a novel topology optimization, which can maximize the average torque of the interior permanent magnet synchronous motors (IPMSMs) in both the maximum torque per ampere (MTPA) and field weakening (FW) regions. In principle, the back electromotive force (EMF), which is proportional to a rotating speed, should be suppressed below the dc-link voltage to protect a power supply system. However, because the design and current reference of the IPMSM are coupled to affect the back EMF, it has been challenging to simultaneously determine the optimal design and current reference under such a voltage limitation. To solve the abovementioned issue, this article derives the design-dependent FW current reference in terms of the elementwise relative densities, which are set as design variables in topology optimization. In addition, the selection criterion between the MTPA and FW operations is proposed under the same design parametrization. After estimating the motor-design parameters, the proposed method simultaneously determines the optimal design and the corresponding current reference in both the MTPA and FW regions. The simulation and experimental results clearly demonstrate the validity of the proposed method.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Analytical Method to Calculate Inductances of Spoke-Type Permanent-Magnet
           Synchronous Motors With Damping Bars

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      Authors: Yu Zhou;Xiaobao Yang;
      Pages: 8254 - 8263
      Abstract: This article proposes an analytical method to calculate inductances and resistances related to damping circuits of spoke-type permanent-magnet synchronous motor (PMSM) with damping bars. Harmonics of inductances are taken into account analytically in order to obtained the performance of line-start PMSM. Damping bars of spoke-type PMSM are divided into direct-axis and quadrature-axis damping circuits. The magnetic field, self-inductances, and resistances of damping circuits and mutual inductances between damping circuits and stator winding are predicted analytically. The calculating results show that the inductances and resistances of spoke-type PMSM with damping bars by the proposed analytical method are well agreement with that predicted by the finite-element method. The line-start process of spoke-type PMSM with the multidamping circuit model in which the inductances and resistances are calculated analytically is also similar with the experimental results. The finite-element and experimental results confirm that the developed analytical method has high accuracy for predicting inductances, resistances, and performance of spoke-type PMSM.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A 3-DOF Piezoelectric Micromanipulator Based on Symmetric and
           Antisymmetric Bending of a Cross-Shaped Beam

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      Authors: Shijing Zhang;Hongfei Zhao;Xuefeng Ma;Jie Deng;Yingxiang Liu;
      Pages: 8264 - 8275
      Abstract: A three degrees of freedom (3-DOF) piezoelectric micromanipulator (PEMMR) based on symmetric and antisymmetric bending of a cross-shaped beam is proposed in this article. Different from typical scheme of combining piezoelectric stack actuator (PSA) and flexible mechanism in previous micromanipulation devices, this article only utilizes eight piezoelectric ceramic plates to construct actuation units and further to realize 3-DOF motions; it overcomes the disadvantages of complex structure, high capacitance and relatively high cost of traditional micromanipulation devices constructed on PSAs. The structure design and motion principle are presented, and the finite-element analysis method is used to simulate output motions and analyze output characteristics; then a prototype is fabricated and an experimental system is established to implement experiments. The experimental results show that the prototype achieves operating range of 99.28 × 99.09 × 24.19 μm, displacement resolution of 15.74 nm, output force of 57.76 mN and force resolution of 0.067 mN, which successfully verifies the design and analysis. The static capacitance of the PEMMR is only about 13.34 nF per axis. Furthermore, a preliminary application experiment is implemented, in which the non-contact posture adjustment of microsphere with diameter of 500 μm in liquid is successfully achieved by the developed PEMMR.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Investigation of Rotor Topologies for Reducing Torque Ripple in
           Double-Layer IPMSMs for Automotive Applications

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      Authors: Yuki Shimizu;Shigeo Morimoto;Masayuki Sanada;Yukinori Inoue;
      Pages: 8276 - 8285
      Abstract: Interior permanent magnet synchronous motors (IPMSMs) are currently widely used for traction applications. However, the torque ripple in these motors needs to be reduced because it causes vibration and acoustic noise. Accordingly, this study first determines the guidelines for reducing the torque ripple of multilayer IPMSMs and then proposes a double-layer IPMSM with holes drilled in the rotor core. The torque ripple reduction for the proposed rotor structure is examined using 2-D finite element analysis and experiments with prototypes. The analytical results show that, under maximum torque-per-ampere control, the torque ripple using the proposed model was suppressed by 54.8% compared with the reference model while limiting the average torque reduction to 3.6%. Moreover, multiobjective optimization based on the guidelines is performed. With the proposed structure, the torque characteristics at high and low currents are highly correlated, and a similar torque ripple reduction effect is obtained even at low current, which is frequently used in traction motors for automotive applications. Finally, optimization is performed for an IPMSM with other topologies, resulting in verification of the generalizability of the proposed method.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Robust Temporal Logic Motion Control via Disturbance Observers

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      Authors: Chengqian Zhou;Jun Yang;Shihua Li;Wen-Hua Chen;
      Pages: 8286 - 8295
      Abstract: The existing motion control systems are largely concerning given reference tracking or stabilization. High-level of autonomy within robotics and autonomous systems demands new motion control methods to realize more complex goals rather than given references, while maintain involved safety conditions. This article tackles the robust temporal logic motion control problem for a class of disturbed systems. A disturbance observer (DOB) is used for unmatched disturbance estimation, and signal temporal logic (STL) formulas are introduced to express complex sequential tasks. For atomic temporal logic formulas, in order to maximize its robust semantics, a continuous feedback composite controller is constructed by utilizing the transient characteristics of the prescribed performance function and the DOB. We then present a suitable switched control strategy to guarantee the satisfaction of STL specifications consisting of conjunctions of the atomic temporal logic formulas. When the given STL formula is satisfied, the system robustness specified by the user meets the temporal logic specifications. Experimental results are illustrated to verify the effectiveness of the proposed method.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Event-Triggered Distributed Consensus Filtering Based on Interval Analysis
           for Heterogeneous Multienergy Networks With Coupling Output Constraints

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      Authors: Lei Su;Jun Zhao;Wei Wang;
      Pages: 8296 - 8304
      Abstract: This article addresses the distributed consensus filtering problem of heterogeneous multienergy networks, where subnetworks exhibit different dynamics and are coupled by output constraints. The global consensus is reached by propagating constraints between subnetworks in the form of interval vectors. Guaranteed intervals satisfying given constraints are returned, which are then used to correct the local states through the probability density function truncation. Given the dependence and wrapping effects during constraint propagation, a hybrid Newton forward–backward propagation (FBP) contractor is proposed for avoiding overly pessimistic estimates. It extends the FBP contractor by replacing the natural inclusion function with centered forms. In addition, an event-triggered mechanism is designed to enhance the efficiency of constraint propagation, which allows the threshold values to be adaptively adjusted according to interval widths. Finally, the proposal is assessed in a steel industrial gas–electricity network with 25 nodes, and the results verify the performance in estimation accuracy, especially for coupling nodes.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Reinforcement Learning and Optimal Control of PMSM Speed Servo System

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      Authors: Jianguo Zhao;Chunyu Yang;Weinan Gao;Linna Zhou;
      Pages: 8305 - 8313
      Abstract: This article proposes a novel model-free optimal speed tracking control scheme for permanent magnet synchronous motors (PMSMs) through reinforcement learning (RL). To achieve the speed servo control, we formulate the linear quadratic regulator associated with the reduced-order model in the outer loop controller design. Such a model is obtained in terms of singular perturbation theory, which enables the separation of slow and fast time-scale dynamics. Moreover, we develop an off-policy RL algorithm to iteratively approximate the ideal value of solution to the linear quadratic regulator without requiring any knowledge of model parameters of the PMSM and the measurement of the load torque. Both simulation and experimental tests are carried out to justify that the proposed control scheme realizes precision speed tracking performance and shape transient response in the presence of unknown model parameters.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Speed and Voltage Controllers Design for the Permanent Magnet
           Starter/Generator

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      Authors: Rui Wang;Zhen Wu;Ping Lin;Xi-Ming Sun;
      Pages: 8314 - 8323
      Abstract: In this article, a linear switched active disturbance rejection controller (LSADRC) is proposed for the speed and voltage control of the permanent magnet starter/generator (PMS/G). Different from the existing works, a type of linear switched extended state observer (LSESO) is newly introduced. The observer gains of the LSESO are not fixed anymore but adaptively changed with the value of the system state. First, the relationships are analyzed between the observer bandwidth and the control performance. Then, the whole working process is divided into three regions by the value of the system state and the switching regulations are designed. Furthermore, the stability conditions are derived for the switched error system with an ensured ${mathcal {L}}_{2}$ gain. Finally, the effectiveness of the proposed method is verified in the 5.5-kW PMS/G platform. The results illustrate the LSADRC can both achieve the smoothness of the control signal and robustness of the PMS/G system.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Distributed Predefined-Time Control for Hybrid AC/DC Microgrid

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      Authors: Yu Zhang;Yan-Wu Wang;Xiao-Kang Liu;Wu Yang;Shu-Ming Liang;
      Pages: 8324 - 8333
      Abstract: Due to the popularization of distributed generators (DGs) and diversity of loads, hybrid microgrid, mixing AC/DC subgrids, has gradually become a popular research topic. However, there is lack of research results to achieve the control objectives of precise AC/DC bus voltage/frequency restoration and global power sharing among DGs in hybrid microgrid within a predefined time. In this article, a distributed predefined-time controller (DPTC) is designed to achieve the above objectives with unknown load power by employing a class $K^{1}$ function and defining a unified error. The convergence time of bus voltage and output power of converters can be adjusted by a predefined parameter. Moreover, a distributed predefined-time observer is proposed to rely less on direct load measurements and guarantee the controller implementation in emergencies when load information is unavailable. Through hardware-in-the-loop experiment tests, the effectiveness of the DPTC is verified in scenarios of load change and plug-and-play. Comparative experiment indicates that the proposed controller has the potential for convenient adjustment of convergence time and the advantage of small overshoot.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Strong Tracking UKF-Based Hybrid Algorithm and Its Application to Initial
           Alignment of Rotating SINS With Large Misalignment Angles

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      Authors: Jianguo Liu;Xiyuan Chen;Junwei Wang;
      Pages: 8334 - 8343
      Abstract: In this article, the fast and precise initial alignment of the low-cost rotary strapdown inertial navigation system under mooring conditions is investigated. The unscented Kalman filter (UKF) is used to address model nonlinearity and to achieve fast alignment for large misalignment angles. A generalized multifading strong tracking UKF (GSTUKF) is proposed to effectively compensate for the kinematic model errors caused by mooring and rotary motions. The performance of the standard strong tracking UKF cannot be optimal because only a portion of the fading factors associated with the directly observable state variables can be obtained approximately using the analytical method. By contrast, using the iteration method to calculate the full-dimensional fading factors precisely, the GSTUKF has greater robustness and adaptability. To find out the optimal fading factors in real time, the multivariate nonlinear optimization model is first designed, and then the iteration approach based on a hybrid algorithm consisting of particle swarm optimization and beetle antennae search is developed, which has no risk of falling into a local minimum. Simulations and experiments are conducted to validate the GSTUKF's effectiveness. The experiments demonstrate that the proposed method reduces the yaw error by 47.2% compared with the standard strong tracking UKF.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Dynamic Proportional-Integral-Based Event-Triggered Output Feedback
           Control Framework for Networked Mechatronic Systems

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      Authors: Jiliang Song;Dawei Shi;Hao Yu;Yang Shi;Junzheng Wang;
      Pages: 8344 - 8354
      Abstract: In this article, two dynamic proportional-integral (DPI) event-triggering mechanisms (ETMs) are proposed for both the disturbance observation and output feedback control of a class of networked mechatronic systems. First, we consider the accumulative errors of output and control samplings in the ETMs of the sensor/observer and controller/actuator channels, respectively, which are embodied in two positive integral terms. Then, an auxiliary variable associated with the sampling error is designed to enlarge the threshold dynamically for each channel, which can be proved to provide larger interevent times than its static counterpart. Furthermore, a codesign approach for the observer, the controller, and the DPI-type ETMs are developed so that the observation error and the system state are uniformly ultimately bounded. The closed-loop stability is proved theoretically by designing compact invariant sets based on the Lyapunov approach, and the Zeno-freeness of the DPI-type ETMs is also guaranteed. Finally, the numerical examples and comparative experiments on an ultrasonic motor platform show the effectiveness of the proposed DPI-type ETMs in improving the closed-loop performance and reducing the communication rates compared with the static counterparts and the classic proportional-type ETMs.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Model-Free Finite-Set Predictive Current Control With Optimal Cycle Time
           for a Switched Reluctance Motor

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      Authors: Manuel Pereira;Rui Esteves Araújo;
      Pages: 8355 - 8364
      Abstract: Traditional use of predictive control techniques require the knowledge of the systems model to control and the use of constant cycle-time. In the case of a switched reluctance motor its model is highly nonlinear and time-varying with current magnitude and rotor position. The use of look-up tables has been one solution, but requires a complete knowledge of the motor and mismatches from the original model used in the design can happen due temperature variation or changes in operating regimes. To address these issues as well as to increase the tracking performance of current control, a model-free predictive algorithm is developed by updating the next cycle time of the next time step of the predictive control. A new parameter estimation method is proposed that identifies the parameters of the switched reluctance model with low computational burden. Based on knowledge of the parameters at real time, not only the ideal voltage vector is applied at each cycle but the ideal time that each cycle must have is also calculated. As result, the advanced current controller requires almost no knowledge of the motor in use. The performance of the proposed schemes is validated through simulation and by a prototype experimental setup. Experimental data shows a decreasing in prediction error around 78 per cent, when comparing to the predefined model controller.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Novel Data-Driven Approach to Analysis and Optimal Design of Forced
           Periodic Operation of Chemical Reactions

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      Authors: Yuhan Dong;Zi-Qiang Lang;Jun Zhao;Wei Wang;Zhong Lan;
      Pages: 8365 - 8376
      Abstract: Forced periodic operation is a technique that periodically changes the manipulating variable of a chemical reaction system in order to exploit nonlinear dynamics to improve reactant conversion rate. However, the analysis and design of a periodically operated chemical process is a significant challenge. To resolve this problem, recently, nonlinear frequency response (NFR) based methods have been proposed. However, because of the need to derive the NFR from a first principle model, existing NFR methods can only perform qualitative analysis to simple processes and are often difficult to be applied in engineering practice. This article proposes a novel data driven approach to the analysis and optimal design of forced periodic operation of chemical reactions. From the data generated numerically using the first principle model or experimentally from experimental tests, the approach produces a data-driven NFR model that can readily be used for both quantitative study and optimal design of forced periodic operation of any complexities. This can fundamentally address the challenges faced by the existing NFR methods, and provides an effective approach that can potentially be applied in engineering practice. Simulation studies and experimental works are carried out on the application of the new method to an isothermal continuous stirred tank reactor system and a laboratory-scale carbon dioxide absorption process, respectively. The results verify the effectiveness and advantage of the newly proposed data driven approach and demonstrate the potential of the new approach in engineering applications.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Generative Adversarial Learning for Trusted and Secure Clustering in
           Industrial Wireless Sensor Networks

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      Authors: Liu Yang;Simon X. Yang;Yun Li;Yinzhi Lu;Tan Guo;
      Pages: 8377 - 8387
      Abstract: Traditional machine learning techniques have been widely used to establish the trust management systems. However, the scale of training dataset can significantly affect the security performances of the systems, while it is a great challenge to detect malicious nodes due to the absence of labeled data regarding novel attacks. To address this issue, this article presents a generative adversarial network (GAN) based trust management mechanism for industrial wireless sensor networks. First, type-2 fuzzy logic is adopted to evaluate the reputation of sensor nodes while alleviating the uncertainty problem. Then, trust vectors are collected to train a GAN-based codec structure, which is used for further malicious node detection. Moreover, to avoid normal nodes being isolated from the network permanently due to error detections, a GAN-based trust redemption model is constructed to enhance the resilience of trust management. Based on the latest detection results, a trust model update method is developed to adapt to the dynamic industrial environment. The proposed trust management mechanism is finally applied to secure clustering for reliable and real-time data transmission, and simulation results show that it achieves a high detection rate up to 96%, as well as a low false positive rate below 8%.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Semi-Implicit Euler Digital Implementation of Conditioned Super-Twisting
           Algorithm With Actuation Saturation

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      Authors: Xiansheng Yang;Xiaogang Xiong;Zhenyu Zou;Yunjiang Lou;
      Pages: 8388 - 8397
      Abstract: The standard super-twisting algorithm (STA) suffers from the windup problem when the actuator of the underlying controlled system is saturated. In the literature, an extension of the standard STA called conditioned STA was proposed to eliminate the windup effect through the feedback of the saturated control action. However, with the standard STA, the digital realizations of the conditioned STA with explicit Euler methods are prone to result in chattering and zigzag oscillations, which degenerate the control performance when the gains of STA are large or the sampling time-step increases. This article proposes a semi-implicit Euler realization for the conditioned STA to avoid these problems. The control accuracy and robustness of the proposed algorithm are analyzed in a discrete-time manner and it shows the proposed realization algorithm is consistent with the standard STA in terms of control accuracy. In addition, the proposed implementation method does not increase the magnitudes of numerical chattering when the gains of conditioned STA are overestimated and when the sampling time-step is large. The advantages of the proposed algorithm are demonstrated numerically with comparisons with other STA realization schemes through simulations and experiments with a platform of linear motor systems with saturated actuation.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Decoupling Matrix-Based Learning Control Scheme for the Machine
           Directional Register of Roll-to-Roll Systems

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      Authors: Tao Zhang;Zhanpeng He;Zhihua Chen;
      Pages: 8398 - 8407
      Abstract: Roll-to-roll (R2R) printing systems are complex multi-input multi-output systems (MIMO), which makes it difficult to design a register control scheme for them, much less high-precision learning control scheme. In this article, a decoupling matrix-based simplification scheme is proposed to transform the complex MIMO system to be a simple one. According to the transformed system and the Lyapunov stability theory, a decoupling matrix-based learning control (DMBLC) scheme is proposed for the register control of R2R printing systems, while a data-based evaluation index is designed to assist DMBLC to achieve high register precision through continuous learning. The effectiveness of DMBLC is verified by simulations and experiments. Comparisons among DMBLC, dynamic matrix control and fully decoupled proportional differential control are carried out to show the superior performance of DMBLC.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Secure State Estimation for Nonlinear Systems Under Sparse Attacks With
           Application to Robotic Manipulators

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      Authors: Xiaoyu Guo;Chenliang Wang;Zhen Dong;Zhengtao Ding;
      Pages: 8408 - 8415
      Abstract: Secure state estimation against sparse injection attacks and disturbances is a challenging problem of both theoretical and practical importance, and existing results mainly focus on linear systems despite many practical systems being nonlinear. In this article, a novel secure state estimation scheme is proposed for a class of nonlinear systems with application to robotic manipulators. A kind of high-gain K-filters is constructed to estimate the unmeasured states, which can attenuate the disturbances to an arbitrary level. Moreover, a monitoring function and a switching scheme are introduced, which successfully preclude attacked measurements after a finite number of switchings. With these efforts, the proposed estimation scheme steers the estimation error into a residual set which can be made arbitrarily small by properly choosing some design parameters, regardless of the disturbances and possibly unbounded attacks. Both simulation and experimental results on a robotic manipulator demonstrate the effectiveness of the proposed method.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Multi-Hysteresis Control for Minimizing Battery Charging Time Within
           Industrial JEITA Guidelines

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      Authors: Hui Wen Rebecca Liang;Yun Yang;Liangxi He;Jialong Qu;Chi Kwan Lee;Shu Yuen Ron Hui;
      Pages: 8416 - 8425
      Abstract: In common industrial practices, the Japan Electronics and Information Technology Industries Association (JEITA) guideline is widely adopted for battery temperature regulations. However, the conventional JEITA-compliant temperature-regulated current control (TRCC) is generally designed without considering the charging speed. To address this issue, a multi-hysteresis TRCC (MTRCC) is proposed in this article. The proposed MTRCC is designed based on the conventional JEITA-compliant TRCC by dividing the hysteresis band for each temperature reference from one to multiple. As a result, the number of charging current levels is increased from three to multiple, such that the charging speed can be improved according to the analysis. The proposed control inherits the simple and effective temperature regulations of the conventional control, while enhancing the charging speed without additional hardware costs. This approach has potential to be an alternative of the state-of-the-art TRCC in JEITA guidelines for single-cell charging applications. Empirical results validate that the proposed MTRCC (with four hysteresis bands) can achieve faster charging than the conventional control at four different ambient temperatures and the charging speed improvement is more significant when the ambient temperature is higher.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Fixed-Time Prescribed Performance Path-Following Control for Autonomous
           Vehicle With Complete Unknown Parameters

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      Authors: Zhongchao Liang;Zhongnan Wang;Jing Zhao;Pak Kin Wong;Zhixin Yang;Zhengtao Ding;
      Pages: 8426 - 8436
      Abstract: This article investigates the issue of fixed-time path-following control for autonomous ground vehicles (AGVs) with completely unknown parameters subject to preset error constraints. Before converging the path-following errors, a fixed-time prescribed performance control (PPC) protocol is developed to guarantee the selected nonsingular sliding manifold evolving within the preset boundaries. Then, the fixed-time PPC target for the preview error of the AGV can be achieved by satisfying the parameter inequality. Furthermore, the designed adaptive laws can ensure the control accuracy without knowledge of vehicle parameters. Finally, the hardware-in-the-loop tests of multiple maneuvering conditions demonstrate that the proposed fixed-time PPC protocol can provide superior comprehensive path-following performance for the AGV over the conventional fixed-time controller, and the preview error can never violate the prescribed performance constraints.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Filter-Based Disturbance Observer and Adaptive Control for
           Euler–Lagrange Systems With Application to a Quadrotor UAV

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      Authors: Qi Han;Zhitao Liu;Hongye Su;Xiangbin Liu;
      Pages: 8437 - 8445
      Abstract: In this article, a filter-based control scheme is developed for Euler–Lagrange systems with unknown parameter and external disturbance. Two controllers are proposed under the filtering framework, namely the adaptive controller and the disturbance observer-based controller, respectively. A set of low-pass filters is employed in the control design to derive useful filter outputs, which can provide the design freedom for the parameter estimator or the disturbance observer. For the adaptive controller, a certainty equivalent adaptive law is designed in such way that dominates the cross term between the estimation error and the filtered regression matrix to achieve a better performance compared with classical estimators. For the disturbance observer-based controller, a high-gain disturbance observer is constructed for the lumped uncertainty with an arbitrary order for users to determine. Experimental results are presented to verify the effectiveness of the proposed schemes on a quadrotor unmanned aerial vehicle (UAV) in several cases.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Adaptive Terminal Sliding Mode Speed Regulation for PMSM Under
           Neural-Network-Based Disturbance Estimation: A Dynamic-Event-Triggered
           Approach

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      Authors: Jun Song;Yu-Kun Wang;Wei Xing Zheng;Yugang Niu;
      Pages: 8446 - 8456
      Abstract: The speed regulation control issue of the networked permanent magnet synchronous motor system is investigated in this article by utilizing a nonsingular terminal sliding mode control scheme. In order to remove the demand of the prior knowledge for possible lumped disturbance and parameter uncertainties in the permanent magnet synchronous motor system, an adaptive neural network is introduced into the proposed terminal sliding mode control scheme. Moreover, in order to ease the communication overheads of the networked system, a new dynamic event-triggered mechanism with considering the neural network estimation error is employed to schedule the signal transmission between the speed sensor and the remote sliding mode controller. The Zeno phenomena for the developed dynamic event-triggered mechanism is excluded via explicit analysis. It is further shown that by choosing suitable sliding mode parameters, the proposed control strategy can guarantee the convergence of the sliding variable into a practical sliding region as well as the ultimate boundedness of the speed regulation error. Finally, the feasibility and applicability of the proposed speed regulation strategy are demonstrated by simulation results and a real experiment.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Optimal Design of Hammerstein Cubic Spline Filter for Nonlinear System
           Modeling Based on Snake Optimizer

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      Authors: Lakshminarayana Janjanam;Suman Kumar Saha;Rajib Kar;
      Pages: 8457 - 8467
      Abstract: This article develops a new class of Hammerstein adaptive filters that contain a memoryless nonlinear system followed by a linear adaptive filter, where the nonlinear system comprises an adjustable look-up table and a spline interpolator. This article's first effort has been to employ the metaheuristic algorithm (MHA) to the Hammerstein spline adaptive filter (HSAF), where it concurrently updates the weights of spline control points and linear filter based on the estimation problem. A novel MHA called snake optimizer algorithm (SOA) is used to enhance the assurance of convergence, estimated parameter accuracy, and steady-state results. The presented experimental results indorse that the proposed SOA-based HSAF (SOA–HSAF) design exhibits more robust performance in dealing with higher degree nonlinear systems under the Gaussian and non-Gaussian circumstances compared to contemporary design methods like classical, some standard MHAs, and other researchers reported techniques. The achieved simulation results are validated using a TMS320C6713 digital signal processor.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • An Intrusion Detection Method Based on Self-Generated Coding Technology
           for Stealthy False Data Injection Attacks in Train-Ground Communication
           Systems

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      Authors: Xiang-Yu Kong;Guang-Hong Yang;
      Pages: 8468 - 8476
      Abstract: This article investigates the problem of intrusion detection of stealthy false data injection (FDI) attacks in train–ground communication systems. An intrusion detection method is proposed based on the self-generated coding technology. Different from the existing pseudorandom coding generators-based detection methods, the proposed method designs a self-generated multiplicative coding scheme by employing the authentication mechanism, where the coding sequences to encrypt and decrypt the original measurement data of trains are dynamically updated by parsing the latest timestamp online, such that the attacker is not able to obtain the prior knowledge of the coding sequences, which improves the security of the data transmission in the train–ground communication network. Under stealthy FDI attacks, the proposed method increases the output residuals of the remote state estimator, which ensures that the residual-based detector continuously outputs alarm. Furthermore, in order to mitigate the impact of the attack on the system, a dead reckoning algorithm-based defence model is established to reconstruct the position information of trains compromised by the attacker. Finally, the effectiveness and superiority of the proposed method are verified through semiphysical simulation experiments.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Capacitance Estimation Method for DC-Link Capacitors Based on
           Pre-Charging Model and Noise Evaluation

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      Authors: Xun Wu;Kaidi Li;Tianjian Yu;Shu Cheng;Yunkai Huang;Yusong Hu;Chunyang Chen;
      Pages: 8477 - 8487
      Abstract: DC-link capacitor is one of the significant parts of traction converters. Due to the impact of electrical stress, high temperature and humidity, its capacitance degrades faster than expected. Accurate capacitance estimation is critical to the condition monitoring of DC-link capacitors, which is also the basis of online capacitor life prediction. Currently, there is a big challenge for capacitor capacitance estimation in railway applications. The noise fluctuation of the voltage sensor may be nearly equal to that of ripple voltage, leading to the considerable errors of the existing capacitor condition monitoring methods. Therefore, a capacitance estimation method based on precharging model and noise evaluation is proposed in this article. The capacitance is estimated by improved recursive extended least square. The influence of the noise can be effectively reduced and both the calculation accuracy and convergence speed can be well guaranteed through an independent noise estimation model. The proposed method has good immunity in a certain range of signal-noise ratio or signal bias. It shows good performance in experiments.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Time-Series Transfer Learning: An Early Stage Imbalance Fault Detection
           Method Based on Feature Enhancement and Improved Support Vector Data
           Description

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      Authors: Xueqing Ni;Dongsheng Yang;Huaguang Zhang;Fuming Qu;Jia Qin;
      Pages: 8488 - 8498
      Abstract: Early stage fault detection plays a pivotal role in Industrial equipment accidents avoidance and scientific maintenance. While limited by the complex operation background, its application encounters with the conundrum of fault feature indistinctness. To address the challenge, a time-series transfer learning (TSTL) method is proposed, which contains two phases: first, early stage series are transferred to their corresponding serious stage for fault feature enhancement. Moreover, due to the improvement of model structure and loss function, the limitation of mismatched working condition is well-weaken. Second, a transferred fault mode recognition model is trained by using transferred normal series that provides a novel solution for data imbalance. Finally, the TSTL method is verified by actual vibration datasets of power pole tower bolts. Its superiority in feature transfer and fault detection is confirmed by several groups of comparative experiments and results demonstrate TSTL outperforms mainstream methods.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Battery Capacity Estimation Framework Combining Hybrid Deep Neural
           Network and Regional Capacity Calculation Based on Real-World Operating
           Data

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      Authors: Qiushi Wang;Zhenpo Wang;Lei Zhang;Peng Liu;Litao Zhou;
      Pages: 8499 - 8508
      Abstract: Efficient battery capacity estimation is of utmost importance for safe and reliable operations of electric vehicles (EVs). This article proposes a battery capacity estimation framework based on real-world EV operating data collected from forty electric buses of the same model operating in two cities. First, a reference capacity calculation method is presented by combining the Coulomb counting method with the incremental capacity analysis method. Then, the impacts of temperature, current, and state-of-charge on battery degradation are quantitatively analyzed. Using the historical probability distributions as battery health features, a hybrid deep neural network model that combines a convolutional neural network with a fully connected neural network is proposed for battery capacity estimation. The validation results show that the proposed model outperforms the state-of-the-art methods and reaches a mean absolute percentage error of 2.79%, while maintaining low computational cost.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Application of a Rogowski Coil Sensor for Separating Internal and External
           Partial Discharge Pulses in Power Transformers

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      Authors: Sajjad Sharifinia;Mehdi Allahbakhshi;Teymoor Ghanbari;Hossein Pakniat;
      Pages: 8509 - 8516
      Abstract: Partial discharge (PD) measurement is an essential tool for evaluating the health condition of a transformer insulation system. The conventional PD measurement systems have a major drawback since they cannot discriminate the internal PD pulses and external pulse-shaped interferences, especially in online and on-site conditions. Various denoising techniques (e.g., wavelets) have been also used in the literature, which are effective for extracting the PD signal from the noisy signals or classifying the PD types. However, the PD pulses and some of the randomly external pulse-shaped interferences have similar time–frequency characteristics, which makes them difficult to separate. In this article, a new cost-effective and simple logic method is proposed for the separation of these interferences. This uses the polarity comparison of the output voltages of the Rogowski coil sensor, mounted on the bushing, and measurement impedance, connected to the test tap. The same polarity represents the internal pulse, whereas the opposite polarity indicates the external pulses. A distribution transformer ($20/0.4{rm{ kV}},{rm{ }} 500{rm{ kVA}})$ and a condenser bushing ($72.5{rm{ kV}})$ were considered to evaluate the performance of the proposed system. The results confirm the effectiveness of the proposed PD measurement system for separating the pulses.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Adaptive Condition Monitoring for Fuel Cells Based on Fast EIS and
           Two-Frequency Impedance Measurements

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      Authors: Pengkun Jiang;Jian Chen;Lei Jin;Lalitesh Kumar;
      Pages: 8517 - 8525
      Abstract: This article proposes an adaptive condition monitoring method for proton exchange membrane fuel cells based on fast electrochemical impedance spectroscopy and two-frequency impedance measurements. First, an impedance measurement system is developed to achieve fast electrochemical impedance spectroscopy and impedance measurements of single frequency. Second, two characteristic frequencies of the fuel cell stack are adaptively extracted from the impedance spectrum. With the two characteristic frequencies, an online state classification algorithm is proposed based on a multiclass linear discriminant classifier to realize the condition monitoring for fuel cells. Finally, the results are validated experimentally on a 3-kW and a 400-W fuel cell stack to verify the effectiveness, rapidity, and migrability of the proposed method.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A Bioinspired Navigation System for Multirotor UAV by Integrating
           Polarization Compass/Magnetometer/INS/GNSS

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      Authors: Shanpeng Wang;Zhenbing Qiu;Panpan Huang;Xiang Yu;Jian Yang;Lei Guo;
      Pages: 8526 - 8536
      Abstract: Stable and accurate heading angle estimation is challenging for low-cost small unmanned aerial vehicle (UAV) navigation, especially in the presence of geomagnetic anomaly. In this article, a bioinspired integrated navigation system (BINS) is designed such that the environmental adaptability of the navigation system can be enhanced. A bioinspired integrated navigation algorithm is presented to fuse the information of polarized skylight, geomagnetic field, inertia, and global navigation satellite system. The relationship among ambient light intensity, degree of polarization, and accuracy of polarization compass is revealed. Thus, the integrated polarization compass can be adapted to more complex weather conditions. A tightly coupled integrated navigation model is developed for BINS to fuse the information of polarization compass and magnetometer. Within the developed scheme, the polarization compass can not only correct the heading error of the system, but also help the magnetometer reconstruct the actual local geomagnetic field distribution. The problem of inaccurate geomagnetic field model in the magnetic anomaly environment is addressed. Moreover, the Chi-Square test is used to detect polarization compass outliers such that the navigation modes can be switched promptly. Finally, the ground static experiments and UAV flight tests are carried out. In comparison to traditional polarization navigation and geomagnetic navigation, the proposed system effectively improves the heading accuracy.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Binocular Vision-Based Method Used for Determining the Static and Dynamic
           Parameters of the Long-Stroke Shakers in Low-Frequency Vibration
           Calibration

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      Authors: Ming Yang;Wenfeng Liu;Zhihua Liu;Chenguang Cai;Ying Wang;Jing Yang;
      Pages: 8537 - 8545
      Abstract: The long-stroke shaker is essentially required for the calibration of low-frequency vibration transducers, whose performance parameters have significant impact on the calibration accuracy. The accurate measurement of these parameters is the prerequisite to establish a reliable vibration metrology and traceability system. Currently, an optical collimator or a reference accelerometer is applied to get the static parameter, the laser interferometry or triaxial sensor-based method is used to obtain the dynamic parameters. However, the former relies on an extra device which increases the complexity and cost of calibration system, and the latter is always difficult to accomplish the accurate and efficient measurement of these parameters. In this study, a binocular vision-based long-stroke shaker performance measurement method is investigated, which has ability to determine the static and dynamic parameters simultaneously during the calibration. This vision method obtains the shaker's bending by measuring the inclinations at the different positions of its guideway, and achieves the amplitude characteristic, distortion, repeatability as well as transverse ratio measurements by accurately acquiring the spatial displacements at different frequencies. Comparison experiments with the two commonly used inclination estimation methods, and the laser interferometry and sensor-based method demonstrate that the investigated method is able to get the satisfactory accuracies both for the static and dynamic parameters of long-stroke shaker in vibration calibration.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Development of a High-Performance Microaccelerometer With Position
           Independent Pure-Axial Stressed Piezoresistive Beams

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      Authors: Mingzhi Yu;Libo Zhao;Xiangguang Han;Chen Jia;Yong Xia;Ping Yang;Yun Zhang;Junjie Sun;Guangzhao Qin;Zhuangde Jiang;
      Pages: 8546 - 8556
      Abstract: It has been demonstrated that piezoresistive beams in a purely axial deformation state significantly enhance the performance of piezoresistive accelerometer. Current solution to realize purely axial deformation of piezoresistive beams for the high-performance microaccelerometer relies heavily on beam positions, which limits its design flexibility and the error tolerance in the fabrication process. In this article, a novel structure with position independent pure axially deformed piezoresistive beams is proposed. By controlling synchronous displacements at both ends of piezoresistive beams, the pure axially stress states of the piezoresistive beams can be easily realized at any beam position without tedious theoretical calculations. The theoretical model was developed to understand the relationship between the displacement and the axial stress of the piezoresistive beams, as well as the natural frequency of the whole structure. Then, the correctness of the theoretical model was verified by finite element simulation and experiments. The results demonstrated that the accelerometer had an extremely high sensitivity of 2.44 mV/g/5 V (without circuit amplification), and a high natural frequency of 11.4 kHz.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • A New Correction Method of Distributed Magnetic Sensor System Based on
           Magnetic Shielding Room

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      Authors: Shengxin Lin;Donghua Pan;Yiding Wang;Lei Wang;Liyi Li;
      Pages: 8557 - 8567
      Abstract: Distributed Magnetic Sensor System (DMSS) can measure vector magnetic field and magnetic gradient tensor (MGT) and is widely used in magnetoencephalography, geological exploration, magnetic navigation, magnetic positioning, and other fields. The posture and position of the magnetic sensor are the key factors that affect measurement accuracy. For the first time, using a magnetic shielding room (MSR) and a composite coil that can switch between uniform and gradient fields in situ, a new correction method for various errors is proposed to reduce vector measurement errors. In addition, sensor position deviation can also lead to MGT calculation errors. This article establishes a compensation model by using the magnetic field gradient formula. The simulation results show that the average calibration errors of the posture and position of the magnetic sensor are 0.08% and 0.53%, respectively, and the measurement error of the MGT is reduced by four times. Experimental results in the MSR show that the measurement error of the vector magnetic field is reduced by two orders of magnitude and that of the MGT by one order of magnitude. Therefore, the new calibration method can effectively enhance the measurement accuracy of the DMSS.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Hybrid Data-Driven Optimization Design of a Layered Six-Dimensional FBG
           Force/Moment Sensor With Gravity Self-Compensation for Orthopedic Surgery
           Robot

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      Authors: Tianliang Li;Fayin Chen;Zebin Zhao;Qingfeng Pei;Yuegang Tan;Zude Zhou;
      Pages: 8568 - 8579
      Abstract: In this article, we develop a layered six-dimensional (6-D) FBG force sensor to detect the interaction force between drill and tissue in robot-assisted bone drilling. Eight unique C-shaped beams are arranged in layers within the structure to constitute a force-sensitive 3-D-printed flexure body and eight FBGs have been tensely suspended on the concave side of beams, leading to low chirping risk and low cost of the designed sensor. A mathematical sensing model of the designed sensor has been derived by response surface methodology with the hybrid data obtained from experiments and the finite-element method. Multiobjective optimization model of the sensor with consideration of machining deviation has been built, and its measurement isotropy for force and moment has increased by 31.4% and 30.7%, respectively, as well as the enhancement of the capabilities of the interdimensional decoupling and toleration for machining deviation. The experimental results demonstrate a low coupling error and a high resonant frequency of more than 232 Hz. The relative error of the sensor is less than 8.27%. A robot-assisted bone drilling experiment has been implemented to further confirm the feasibility and reliability of the sensor. By innovatively integrating a gravity self-compensation method, the sensor's detected force agrees with the reference result with a less error of 7.4%.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Electronic Safety System for Table Saw

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      Authors: Federico Cavedo;Parisa Esmaili;Michele Norgia;
      Pages: 8580 - 8587
      Abstract: This article proposes a safety sensor for table saw, based on impedance measurement between two electrodes placed in front of blade. A multitone system is developed, acting as a selective barrier able to distinguish the proximity of a hand with respect to wood, both dry and wet. Due to conductivity of human body, the proximity of the hand introduces a shielding effect, causing a reduction in capacitive coupling between electrodes. On the contrary, wood cannot induce the same effect for all frequencies, even if it is wet. This results in achieving a very sensitive and cost-effective safety system, able to respond effectively to hazard situations. An electronic prototype, realized through digital synchronous detection of two tones at 10 kHz and 1 MHz, demonstrates the effectiveness of the proposed sensing technique. To better describe the working principles, a simple system simulator is studied, able to describe the experimental results. The proposed technique opens the way to a new generation of safety systems for table saw.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Reducing Leakage Current Using LTPS-TFT Pixel Circuit in AMOLED Smartwatch
           Displays

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      Authors: Chih-Lung Lin;Po-Cheng Lai;Jui-Hung Chang;Yi-Chien Chen;Po-Chun Lai;Li-Wei Shih;
      Pages: 8588 - 8597
      Abstract: This article proposes a new pixel circuit that is operated at a low frame rate using low-temperature polycrystalline silicon thin-film transistors (TFTs) for use in active-matrix organic light-emitting diode (AMOLED) smartwatch displays. The proposed circuit uses a new leakage-prevention method (LPM) to balance the off currents at the gate node of the driving TFTs, eliminating the drop of the driving voltage. Uniform OLED currents are thus generated throughout the extended emission period. Also, the OLEDs are all turned off except in the emission stage to suppress image flicker. To confirm the feasibility of the proposed pixel circuit, a 1.41-inch panel, based on the proposed circuit, is fabricated. Experimental results demonstrate that diminishing the off currents maintains the driving capability of the pixel circuit to stabilize the luminance of the fabricated panel. The exhibitions of red, green, blue, and white images at frame rates from 60 Hz to 15 Hz are uniform, verifying that the proposed pixel circuit with LPM has high potential for use in AMOLED smartwatch displays with a low frame rate.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • Sequence-Admittance Measurement Method of Grid-Connected Inverter With Its
           Control System Disturbance

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      Authors: Zhiwei Xie;Wenhua Wu;Yandong Chen;Shixiang Cao;Yuancan Xu;
      Pages: 8598 - 8602
      Abstract: The impedance or admittance characteristics of the grid-connected inverter play an important role in its stability analysis. The traditional sequence-admittance measurement methods of the grid-connected inverter mostly rely on special admittance measurement equipment or adjacent grid-connected inverters for disturbance injection. Because of high hardware cost or inconvenience, the abovementioned methods are not suitable for price-conscious testers to some extent. To address the abovementioned issues, this article proposes a sequence-admittance measurement method of the grid-connected inverter with its control system disturbance. First, the sequence-admittance model of the measured grid-connected inverter when small-disturbance signal is superimposed on its modulation signal is deduced and the system equivalent circuit model is built. Then, the flow chart of the proposed sequence-admittance measurement method is designed. According to the injected small-disturbance signal, the output voltage and inductor current of the grid-connected inverter, the sequence-admittance characteristics in sub/supersynchronous frequency area can be obtained. The measurement process does not need the cooperation of external disturbance source, which saves costs and improves the measurement convenience. Finally, experiments verify the effectiveness of the proposed sequence-admittance measurement method.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
  • An Ultra-Low Power Soft-Switching Self-Oscillating SIMO Converter for
           Implantable Stimulation Systems

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      Authors: Hyeon-Ji Choi;Chisung Bae;Yeunhee Huh;Sang Joon Kim;Seungchul Jung;Kye-Seok Yoon;Joo-Mi Cho;Hyo-Jin Park;Chan-Ho Lee;Su-Min Park;Esun Baik;Young-Ju Oh;Ho-Chan Ahn;Chan-Kyu Lee;Sung-Wan Hong;
      Pages: 8603 - 8608
      Abstract: This letter proposes an ultralow power single-inductor multiple-output converter for an implantable stimulation system. This converter minimizes the number of switches turning on and off to deliver power to outputs of 0.8, 1.8, and 20 V, and it uses a soft-switching technique for all switching nodes. It also operates with a self-oscillating controller only when outputs require power. As a result, it has a peak efficiency of 92.3% when the converter generates the outputs of 0.8 and 1.8 V, of which load currents are 2 and 0.5 mA, respectively, from a battery voltage of 3 V. The converter consumes a quiescent power of less than 3.0 μW.
      PubDate: Aug. 2023
      Issue No: Vol. 70, No. 8 (2023)
       
 
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